How to Redline a PDF Using Legal AI

In Chuck Kable's first week as general counsel at Innovative Renal Care, a kidney-care provider with nearly 250 dialysis centers in the United States, a request for a standard nondisclosure agreement took two or three days and involved three lawyers.

He later described a process that let colleagues create a PDF from a standard form and kept a Word copy for the legal team if the other side wanted changes.

If someone sends you a PDF and asks for changes, you have two ways to handle it:

• Add comments to the PDF. Suggest replacement wording or cross out words you want removed.

• Use tracked changes in Word. Ask for the Word file, or convert the PDF and check the result. Both sides can then accept or reject each edit.

GC AI is an enterprise legal AI platform that helps in-house legal teams review contracts and draft redlines in Word. Give it the PDF and your company's preferred terms. It can flag differences and help you prepare changes based on those standards.

As of November 2026, GC AI is trusted by 2,100+ legal teams and 300+ public companies. Customers range from solo GCs to Fortune 500 companies.

Check the PDF Before Editing

Before you use either method, keep the original PDF and work on a copy. Make sure you also have any attachments or later changes to the agreement, such as schedules, exhibits, and amendments.

Next, check two things:

• Permissions: A PDF can permit comments while restricting other changes. Confirm that the sender permits the intended editing or conversion, and use a tool approved for the document's data. Adobe treats commenting and editing permissions separately.

• Text quality: Try selecting and copying a sentence, including its numbers and punctuation. A scan may contain only an image of the page. Optical character recognition, or OCR, turns the words in that image into text software can read. Even selectable text can contain recognition errors, so compare it with the page image.

Acrobat can apply OCR to scanned documents. Check the text it produces against the scan before using it. If you can't read the original clearly, ask for a better scan or the original document.

How to Redline a PDF in Adobe Acrobat

Once you've checked the PDF, use comments and markup to suggest changes without replacing its text. In desktop Acrobat, here's how to suggest a text replacement:

1. Open the working PDF.

2. Select Add a comment from the Quick action toolbar.

3. Select Replace selected text.

4. Select the words you want to replace.

5. Type the proposed replacement in the pop-up box, then select Post.

To suggest removing words, select them and use strikethrough markup. Add a comment to explain why. To suggest adding words, show exactly where they belong and write out the full wording you want.

Give the person updating the agreement enough detail to make the change. For example: “In Section 4.2, change 30 days to 45 days. Keep the payment period starting when the customer receives the invoice.” That tells them what to change and what to keep. “Revise payment terms” leaves them to work out the wording.

Read all your comments before saving. Make sure each one points to the right text and that the instructions agree with each other. Someone will still need to put the agreed changes into the contract.

Compare Two PDFs

When the other side returns a revised PDF, compare it with the version you sent to see what changed. In Acrobat Pro:

1. Select All tools > Compare files.

2. Choose the version you sent as the old file and the returned version as the new file.

3. Check the comparison settings, including the page range and document type.

4. Select Compare, then review the results in the new comparison document.

5. Save the report with the two source files.

Check the filters before you rely on the report. By default, Acrobat does not show differences in comments and markup, formatting, or backgrounds. Turn those filters on if you need them. The Compare text only setting leaves out differences in graphics.

The report shows where to look. Read each changed clause alongside the related terms: a new payment deadline, for example, may also affect when interest starts or when the supplier can stop providing service. Check any difference you can't explain, even if it looks like formatting.

If your team works with several file types, the legal document comparison software guide can help you choose a tool that supports them.

Convert the PDF to Word

If you need edits the other side can accept or reject, ask for the original Word file first. If you only have a PDF and have permission to convert it, open it in Word and save it as a .docx file. Tables, footnotes, endnotes, PDF comments, and tracked changes may not convert correctly, so check the result before editing.

If you started with a scan, check the OCR text first. Then put the Word copy beside the original PDF and compare them before changing the contract:

• Text and numbers: Names, dates, amounts, percentages, words such as “not,” and payment deadlines.

• Structure: Definitions, numbering, headings, and references to other sections.

• Tables and attachments: Row labels, units, prices, and any attached documents or terms included by reference.

• Page elements: Headers, footers, signature blocks, and content near page breaks.

• Earlier feedback: Comments and markup that you still need to keep.

Fix any conversion errors so the Word copy matches the original PDF, and note what you fixed. This checked copy is your baseline: the starting point for tracking your changes. If you can't tell which wording or number is correct, ask the sender. You can leave PDF comments to explain the changes you want while you wait.

Save the checked Word copy. Then make another copy and turn on Track Changes before you edit. This keeps fixes to conversion errors separate from changes you want the other side to accept. The Word redlining guide explains how to show, accept, and reject those changes.

Change a Payment Deadline

Here's an example that puts those checks into practice. You're reviewing a supplier contract and want more time to pay, but first you spot a conversion error. This example has not been tested in the products.

You represent the customer. Your company wants 45 days after receiving the supplier's invoice to pay amounts it does not dispute. In this example, someone in Finance must approve any decision to keep the supplier's 30-day deadline. The received PDF contains this clause:

Customer shall pay all undisputed amounts within 30 days after receipt of Supplier's invoice.

The pricing schedule states $10 per user per month. Suppose the converted Word table instead says $100 per user per month.

First, correct the price to $10 and save the checked Word copy. Then make a new copy, turn on Track Changes, and propose 45 days instead of 30. This makes it clear that the price change fixes an error, while the payment change asks for a new term.

Keep a Record of Your Changes

A short record helps the next reviewer follow what you did. Record the original file, any conversion fixes, and the changes you want the supplier to accept. Replace the examples below with your contract's details:

If you can't read the original price, mark it “unresolved” and name who will ask the sender to confirm it. Don't guess.

Review and Redline With GC AI

You can start with the PDF while you wait for a Word file. Give the GC AI web app the PDF and explain that you represent the customer and want 45 days to pay. Ask it to find the payment clauses, cite them, and show what needs to change. Include rules about disputed bills, late interest, and when the supplier can stop providing service. Ask it to list missing facts and decisions for you or Finance separately from suggested edits.

With Exact Quote, click GC AI's citation to open the source document with the quoted words highlighted. Read the surrounding section to see whether another payment clause changes when payment is due or what the customer owes.

Once the Word copy matches the PDF, open it in GC AI for Word. You can request a redline to a clause, section, or whole contract and review the proposed changes in Word before deciding what to send. For this example, tell GC AI what to change and what to keep:

Example prompt: 45-day payment redline

Represent Customer. In Section 4.2, change the payment period from 30 days to 45 days after receipt of Supplier's invoice. Preserve the limitation to undisputed amounts and the existing invoice-receipt trigger. Propose the change as a tracked revision. Identify any conflicting payment deadlines, late-interest provisions, or suspension rights elsewhere in the supplied agreement for my review. Draft a brief counterparty comment stating the proposed payment period and asking whether Supplier can accommodate it. Keep the internal Finance-approval requirement out of counterparty comments.

The intended clause is:

Customer shall pay all undisputed amounts within 45 days after receipt of Supplier's invoice.

Compare the proposed clause with the original. It should still cover only amounts the customer does not dispute, with the 45-day period starting when the customer receives the invoice.

Check whether other payment deadlines, interest terms, or rights to suspend service also need to change. If you have asked Finance to approve 30 days instead, keep that decision marked as pending in your internal notes until you have an answer.

To reuse your team's payment position across reviews, set the preferred term and allowed alternatives in Playbooks. GC AI checks agreements against those standards, including in Word, and flags issues for your review. You decide which option fits this contract.

Hayley McAllister, Senior Counsel and Head of Commercial Legal at Jasper, handles both customer and vendor contracts. She describes how GC AI for Word fits into that work:

Once the Word plugin rolled out, I pretty much exclusively started using it for all of my redlining and contract review.

McAllister uses GC AI to change specific wording and draft comments explaining Jasper's position. That's the same approach used here: request the payment change, explain it to the supplier, and review the result.

The video below shows how to review and redline a contract with GC AI in Word:

Check the File Before Sending

Once you're happy with the edits, open the saved file you plan to send. Check that it contains the right proposals and comments. Keep internal approval notes and details about what your company might accept in your team's own record.

If you're sending a PDF, Acrobat's sanitization tools can remove hidden information, but they can also remove comments. Use them on a copy and choose what to remove. Reopen the saved file to make sure the comments and changes you want to share are still there.

If you're sending a Word file, check the tracked changes. If you're also sending a clean copy, check that it shows the same proposed wording without the change marks. Say which version you started from, flag anything you still need the sender to clarify, and name who will handle the next step. Label the clean copy “proposed” until both sides agree on the terms.

To try this with GC AI, bring a supplier PDF your team is allowed to share, a checked Word copy, and your company's payment requirements.

Ask GC AI to find the payment terms, suggest a tracked edit, and draft a comment for the supplier. Review the sources and proposed wording, then note any corrections you need to make. That gives you a practical way to judge how well it fits your team's work.