You could amend your statement of intention, and the court doesn't charge for such an amendment. However, doing so is not necessary. A statement of intent is just that, "intent." If you change your mind and don't carry out that intent, so be it. You didn't reaffirm the debt.
No, the statement of intention you file with your bankruptcy is virtually meaningless. If you say you intend to surrender, the lender may begin foreclosure or repossession efforts sooner rather than later. Hope this perspective helps!