Have Copilot repair an existing pull request

A developer used GitHub Copilot to patch a PR, but it created a separate PR instead of updating the original branch.

Done with GitHub Copilot· Intermediate· Feb 2026

What they did
The developer opened a pull request and then followed Copilot’s own instruction to mention @copilot in a comment when they wanted changes. They asked it to fix their PR and expected the edits to land on that same branch. Instead, Copilot spun up a new pull request, which would have forced them to merge the changes back by hand.
How it went
GitHub later added support for Copilot to modify any pull request. Even so, Stephen Toub said it still breaks when the source branch lives in a fork, which is the case for almost all human-authored PRs in dotnet/runtime.
Tips
Before relying on this flow, check whether the PR branch comes from a fork. If it does, Copilot may still be unable to update it in place.

Try it yourself with GitHub Copilot

You are helping with an open pull request in [owner/repo]. Review PR #[PR number] and the issue or review comment at [link or short description]. Make the smallest safe change to address [bug, lint failure, or review request], then pause and ask me to approve before doing anything irreversible, including submitting the change if it would create a new PR instead of updating the existing one. If you can update the current branch, do that; if not, explain why, list the exact files you would change, and wait for my approval before proceeding. Stop after the fix is ready or you have explained the blocker.

Fill in the [brackets]. Agents can make mistakes, so review anything before it is sent, paid or deleted.

Read the original on github.com ↗

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