Identifying light socket in kitchen
Those have ballasts in them, so it's not a simple re-wire, per se. Nor do I think any adapter would be available, because of that.

You'd have to swap the guts out (the inner can) with one from a new can, and hopefully it will fit (they're not fun to get back into the can they came out of in the first place, so expect some difficulty).

I don't think you can buy 'can innards'; you'll be buying a whole new can light and just using parts of it.



Another consideration is determining if they're IC can lights (Insulation Contact) and if so, finding the correct replacement 'innards'. But I don't think that's a concern; the 'IC' part of it, is the shell that will remain. I'd just make sure that any replacement had an over-temp cutoff switch.