If you have your password saved on CrewBuddy for Android then just deleting won't work.  

You'll have to change your device administrator setting first.

1. "Settings"

2. "Security" (Sometimes called lock screen and security)

        2a. If on a Samsung device, then go to "Other security settings"

3. "Device (Phone) administrators"

4. Untoggle/Uncheck CrewBuddy