doing your first whole sale contract correctly

[James Lopez]

Hi my name is James Lopez, i am new to the business and about to put my first offer for a whole sale deal in San Antonio TX.  I am just a little stuck on how to protect my self on the contract in case my buyers see a higher rehab cost than i am expecting and im not able to complete the sale.  This deal looks promising in a very desiring historical area but being that it will be my first deal i just want to make sure that i don't get stuck on a contract for a home that i have no plans on keeping. 

Any advice is much appreciated.