This really depends on the Lender, the Investor and the servicer's negotiator. I have had some say that is not a big deal and others that say they need to go through the entire approval process again. It will often depend on who the second buyer is. If it is a spouse, it usually goes through easily. If it is an unrelated party, this will usually put you back a few steps in the approval process, and may derail the approval entirely. Have the listing agent check with their negotiator on this. If it looks like it will be a problem, just close with the original buyer and then add the second party to the title after close of escrow.
Just curious, is the second buyer being added in order for you to qualify for the loan? If this is the case, be up front with the negotiator and let them know this is what is needed to complete the sale. That may help get the approval more quickly.
Remember, most short sale approvals are buyer specific and have language to the effect that any change in buyer, seller, or other terms of the sale MUST be approved by the short sale lender. Title will require that you adhere to all terms of the short sale approval in order to issue insurance. Hope this helps. Dare to Dream.
Shel-lee Davis, CDPE, SFR, QSC
Your Real Estate Consultant for Life
RE/MAX Palos Verdes Realty