Removing a Group admin/s is easy. Simply:
- Open the Insight Timer app on your device.
- Tap the menu icon (☰) in the top-left corner.
- Scroll down and select "Groups".
- Enter the Group.
- Tap Settings at the top right corner of the screen
- Scroll down to see the members.
- Select the profile icon of a current Admin which you'd like to remove.
- Select Remove Admin.
Please remember that you also must be an Admin to remove an Admin. Here's how to assign an admin.