unpin

verb4

1. •
   To unfasten by removing a pin.
2. •
   To detach (an icon, application, etc.) from the place where it was previously pinned.
3. •
   To undo the pinning or fixing of (an array in memory, a security certificate, etc.) so that it can be modified again.

   • […] you can use the GCHandle class mentioned earlier to pin a heap block until you explicitly unpin it. — 2012
4. •
   To get (a piece) out of a pin.