General:
* Detach
* Separate
* Withdraw
* Release
* Uncouple
* Disconnect
* Break free
* Cut loose
For relationships:
* Distance oneself
* Break up
* End
* Part ways
* Go separate ways
For physical objects:
* Unfasten
* Unhook
* Remove
* Unscrew
* Unplug
For mental processes:
* Distract
* Divert
* Shift focus
* Lose interest
The best synonym depends on the specific situation and the nuance you want to convey.