METHOD1->
Since origin already exist remove it.
git remote rm origin
git remote add origin https://github.com/USERNAME/REPOSITORY.git
METHOD2->
One can also change existing remote repository URL by ->git remote set-url
If you're updating to use HTTPS
git remote set-url origin https://github.com/USERNAME/REPOSITORY.git
If you're updating to use SSH
git remote set-url origin git@github.com:USERNAME/REPOSITORY.git
If trying to update a remote that doesn't exist you will receive a error. So be careful of that.
METHOD3->
Use the git remote rename command to rename an existing remote.
An existing remote name, for example, origin.
git remote rename origin startpoint
# Change remote name from 'origin' to 'startpoint'
To verify remote's new name->
git remote -v
If new to Git try this tutorial->
TRY GIT TUTORIAL