You didn't mention whether the payment was by check or by EFT. An EFT payment cannot be deleted after the bishop's approval. A Check can be voided as long as the procedures in the Help Center article,
Voiding a Check, are followed. Essentially this involves returning the check to the clerk; the clerk voiding it in LCR Finance; removing the signature blocks on the check; writing 'VOID' in large letters across the check, and attaching the voided check to the batch report for the check.
In the case of the EFT payment, the payee will have to use a paper Tithing and Other Offerings slip to return the extra payment. The payee fills out the slip with the budget category written in the 'Other' block on the slip and enter the returned amount in the block to the right. Returns of this extra payment cannot be made online since there is to provision to do this.