Short sale approvals rarely take 3-6 months anymore if the listing agent and/or short sale processor is experienced and knows how to submit the paperwork properly.
It will depend on the bank, investor, age of previous approval and appraisal on file, on a variety of other components but it is definitely possible to get an approval re-issued in just a few weeks.
If the appraisal the bank has on file has expired and they order a new one, it could delay the process by another 1-3 weeks.
Make sure the agents are updating you on progress every 1-2 weeks and don't start to panic if it does take 30-60 days. The good news is that if it was approved once (and there haven't been any significant changes to the property, the market value, or the seller's finances) chances are good that it will be approved again.
Brian Walsh ABRÂ® BPO