Can I change my withdrawal after I receive it?
Once your withdrawal is processed, you cannot return it or change the withdrawal option. However, if you elected to receive all or a portion of your account in a series of monthly payments, you can change your election to a final single payment or change where your payments are being sent. Effective each January, you can change the fixed dollar amount you are receiving. During that time, you can make a one-time change from TSP-computed monthly payments based on life expectancy to a fixed dollar amount.
Use Form TSP-73, Change in Monthly Payments, to request a change to your monthly payments. You can change to a final single payment at any time; however, in order to change from TSP-computed payments to a specific dollar amount or change the dollar amount you are receiving, your Form TSP-73 must be received by the TSP by December 15 in order to be effective January 1 of the following year.