Once a Retainer Deposit has been saved, you cannot change the amount field.  If it was entered for the wrong amount you will either have to delete the transaction or enter a RDS through AR Entry for the difference in the amounts.  If you catch the error right away you will be able to delete it; however, if an Invoice has been generated on the Client-Matter since entry of the RDP, you will have to enter a RDS to reduce the retainer balance.  We suggest you place a short explanation in the description field to explain the RDS – for example, “to reduce original amount of RDP entered incorrectly.”