Captive nuts!!

[fasterfaster1]

Because these mushroom out from underneath the same as a rivet when fitted Bear, I doub't you will get it out as it is without making the hole bigger. The only way I could see would be to drill a hole in it and then get a small die grinder and actually cut it thru to one side so that you can squeeze, as in collapse it and then withdraw it from the hole. The other option may be to pean around the edge of it with a sharp centre punch so as to tighten it enough to be able to turn and get the bolt piece out and then with the fitting tool designed to fit these, retighten the insert in the hole.
Cheers
FF1 <i></i>