This is a strange question. The lender cannot change the contract or offer and then approve it without you approving the changes yourself. It's just not possible. The contact is not valid because you have yet to agree to the changes. Does that make sense? What you have stated is not even possible in my opinion.
Anytime any changes are made to any purchase contract, foreclosure or or traditional, all parties need to approve.
Most foreclosures and short sales allow for an option period of 10 days. In this situation an option fee is typically not charged but is given to the buyer. Your contract or an addendum will state this.
Please talk to your Realtor or their Broker if you have any other questions. It seems like you are not getting the information you need from them and information is critical in making good decisions and also understanding what your options are.
Best of luck to you.
REALTORÂ® | Mortgage Broker
Keller Williams Realty | 360 Lending Group