http://www.yourdictionary.com/renegotiate
Renegotiating - to negotiate again; specif., to review (a contract) with a view to obtaining more equitable or favorable terms
I hate to use the word never but here it goes. You should never, EVER, renegotiate on the same night, even if she approach you back. If you encounter her on another night then all bets are off because is not a renegotiation but a new deal. My logic follows that either you or the “chica†will have to give something away to consummate the deal that night and that will make a GFE extremely difficult if not impossible.
Express – I know Colombianas that won’t do Afican-Americans no matter what. I know some that won’t do anybody below 50 years old. Is not that they are ugly or anything like that is just a matter of them trying to get the most money for their “poon†and efforts. Some girls will not touch 25-30 years old because they expect to be jackhammer all night. It is impossible to read the girls mind and their logic.
Best advise, approach, negotiate, if negotiations are not successful, walk away. For every “chica†that says NO, there are a thousand waiting with open arms.