To void a deposit, go to the deposit screen, choose the correct bank account and the month/period the deposit occurred.  Next change the Status to All.  If the ID number is known that too  can be entered to filter directly to the deposit in question

A list of all deposits will be displayed.  Click Void

And Yes to confirm.

The deposit will now show as Voided

This cash receipt can now be deposited again or voided as needed.