When you revoke a stall's claim, you get a message a few minutes later (I assume at the duration of a fully claimed stall would naturally be at?) that the stall is no longer rented.
However, if you were to revoke your claim, then come back later to claim it, before your stall 'time' would be naturally up from the first time, your second rentage prematurely ends.
PC: Arnold Berryson
Place: Ticker Merchant Stalls