In the Magpie app, Team settings now has Leave team under Team access for every member of the selected team. After you confirm, the app uses Personal. What you made stays with the team, and your Personal work is not affected. The team's owner sees that the team must be transferred to another admin first, as on the website.
Before, only team admins could leave, from their own row in Team members, and they were sent an email saying they had been removed. Leaving no longer sends that email.