To remove someone from your team or yourself from another member's team, select on the menu icon in the upper right, go to My Profile, then my team.
Once on your team page, find the member and select 'remove from team'.
If you wish to remove yourself from someone else's team, select 'Teams I'm On', then select the small circle with a white V in it to the right of the provider's profile card, and choose 'remove from team'. They'll be removed.
If you wish to block someone, select 'block user from my page' instead of 'remove me from their team'.