To leave a community:
Open the Pray app and tap the profile icon at the bottom right.
Tap the gear icon at the top right.
Tap "Communities" on your Settings.
For Android devices, tap the three dots at the right side of the community and select 'Leave'. For iPhones, swipe left on the community you would like to leave and select 'Leave'.
If you cannot find the three dots to the right side of the community name, this means you are currently selected to the community you would like to leave and first need to switch to another community.