Assuming newBase is the branch you want to move your commits onto, oldBase is the old basis for your branch, you can use --onto for that:
git rebase --onto newBase oldBase feature/branch
Given your case:
git checkout PRO # Just to be clear which branch to be on.
git rebase --onto master demo PRO
Basically, you take all the commits from after demo up to and including PRO, and rebase them onto the master commit.