General:
* Withdrawing
* Recanting
* Taking back
* Revoking
* Canceling
* Rescinding
* Unsaying
* Denying
For physical objects:
* Pulling back
* Drawing back
* Withdrawing
* Reeling in
For statements or promises:
* Recanting
* Disavowing
* Denying
* Taking back
* Backtracking
For a physical part of the body:
* Retracting (this is the most accurate for this context)
* Withdrawing
* Pulling back
The best synonym depends on the specific context of the situation.