Best Offers

[TheOtherMaryPoppinsDiets]

Is there a way to go back and accept a best offer that was auto declined?

nope fraid not!

couldnt you send them a second chance offer?

no, best offers are just that they submit their best offer if you have auto decline on it tells them no right away and gives them an option to have 2 more chances to put a higher offer in.
For the seller they remain pretty anonymous you get 3 random characters from their user ID and a star to indicate approx feedback

You can do a Sherlock Holmes and somtimes work out in advanced search who your buyer is and email them.