Unpin

Verb

1. To unfasten by removing a pin.
2. To detach (an icon, application, etc.) from the place where it was previously pinned.

   "to unpin a program from the Taskbar"

3. To undo the pinning or fixing of (an array in memory, a security certificate, etc.) so that it can be modified again.
4. To get (a piece) out of a pin.