How does one change teams?

Assuming you are talking about changing a team via BAM! here is what you should do:
1. Go to the teams page of your BAM! account.
2. Tick the "Change/Search team" checkboxes of the projects in which you want to change your team.
3. Type the name of the team you want to be part of in the search box at the bottom of the list and click "Search"
4. You will be redirected to page with your search results and a "Join "checkbox. Choose your exact team from the combos (if the search returned more than one team), tick the "Join" checkboxes and press the "Join" button.

Moved your thread to the appropriate forum.