Update documentation

README.md

@@ -88,6 +88,21 @@ If there is some reason you need to use `actions/checkout@v1` the following step
       - run: git checkout "${GITHUB_REF:11}"
 ```
 
+Checking out a branch from a different repository from where the workflow is executing will make *that repository* the target for the created pull request. In this case, a `repo` scoped [Personal Access Token (PAT)](https://help.github.com/en/github/authenticating-to-github/creating-a-personal-access-token-for-the-command-line) is required.
+
+```yml
+      - uses: actions/checkout@v2
+        with:
+          token: ${{ secrets.PAT }}
+          repository: owner/repo
+
+      # Create changes to pull request here
+
+      - uses: peter-evans/create-pull-request@v2
+        with:
+          token: ${{ secrets.PAT }}
+```
+
 ### Branch naming
 
 For branch naming there are two strategies. Create a fixed-name pull request branch that will be updated with new changes until it is merged or closed, OR, always create a new unique branch each time there are changes to be committed.