When someone makes an MR from their own repo on gitlab, the CI sometimes will not run, or you want to add an additional commit.
- Create an MR through gitlab interface
- Go to the external MR and get gitlab instructions by clicking on the "Check out branch" button
- Merge the external MR in the local MR branch
- Rebase on target branch to avoid useless merge commits and complex history
- Commit your own fixes if needed
- Push and Merge after CI