The repository was cloned using a key, but now I need to do a pull using user and password authentication, and doing the git pull won't ask for credentials.
How do I force the pull to ask me for credentials?
I found the solution:
git remote set-url origin https://github.com/USERNAME/OTHERREPOSITORY.git
Found it here: https://help.github.com/articles/changing-a-remote-s-url/