Appraiser seldom change their valuation after they submit.
Here are your options:
1) Sell to the buyer at the appraisal amount.
2) Ask the buyer to bring cash to the table (in addition to their loan amount) that way you still sell for $293 or agree to some number in the middle.
3) Tell the buyer they need to change lenders/brokers .... that way the new company would order a fresh appraisal. (If you think a new appraisal would have value to qualify)
4) List home for cash buyers only
Plus, I would negotiate with the Realtor for a discount on his/her rate to close the deal at any amount with this buyer, since the agent will be picking up both sides of the commission split. (Suggesting an original sales price so far off from market price per this appraisal - has cost you delays.)