For now, until hgtonight adds an option for removing a role and adding a role, I have an alternative for that.
If you want every one of your roles to reward a new role, and let's say you want to give a user a Moderator Rank, but NOT have them go to Level 4 (example) if they get to the point level, here's how...
1: Go to the profile of the user you want to rank them with.
2: Go to the Edit Profile drop-down menu and click on Edit Rank
3: Select the rank you want to award them from the drop-down box, whether that'll be Moderator, Staff, Administrator, etc.
4: BEFORE you click on Save, uncheck the 2nd check box that says: "Allow user to automatically progress past this rank." under Rank Progression.
5: You're done. Now, even though your user can reach the points required for some other Rank, it won't progress them.
Please tell me if I am incorrect about something. Enjoy Yaga!