Merge pull request #1081 from mi6/1330-git

docs(root): added amending a commit guidance

CONTRIBUTING.md

@@ -18,6 +18,7 @@ Welcome and thank you for contributing to the [Intelligence Community Design Sys
   - [Accessibility](#accessibility)
   - [Style guide](#style-guide)
   - [Git commit](#git-commit)
+  - [Amending a commit](#amending-a-commit)
   - [Styling](#styling)
 
 - [Testing](#testing)
@@ -153,6 +154,43 @@ Follow these steps when making a commit:
 8. Provide a link to the issue by entering the reference e.g. `#123`.
 9. When the editor opens up, check your commit message and press `Ctrl`+`x` to confirm.
 
+### Amending a commit
+
+If you need to make changes to a commit (for example, after receiving comments on a PR), follow these steps:
+
+1. **If you're amending the most recent commit:**
+   - Stage your changes using `git add` and include the files you want to update.
+   - Run `git commit --amend --no-edit` to amend the most recent commit without changing the commit message.
+   - The Commitizen prompt will still appear as if you are making a new commit. Exit the prompt (usually by pressing Ctrl+C).
+   - Push the changes to the remote repository using: `git push --force`.
+
+2. **If you're amending an older commit:**
+   - Use `git rebase` to modify an older commit. For example, to modify commit `a1312407`, run:
+     ```sh
+     git rebase --interactive a1312407
+     ```
+
+   - In the default editor, change `pick` to `edit` for the line mentioning `a1312407`.
+
+   - Save the file and exit. Git will interpret and automatically execute the commands in the file, placing you in the state just after creating commit `a1312407`.
+
+   - Amend the commit by making your changes and then running:
+     ```sh
+     git commit --all --amend --no-edit
+     ```
+
+   - The Commitizen prompt will still appear as if you are making a new commit. Exit the prompt (usually by pressing Ctrl+C).
+
+   - Continue the rebase process by running:
+     ```sh
+     git rebase --continue
+     ```
+
+   - Push the changes to the remote repository using:
+     ```sh
+     git push --force
+     ```
+
 ### Styling
 
 - Avoid using inline css.