Womb Chair Reupholster Washington D.C.?  

There's Daniel Donnelly in VA outside of DC if you don't mind paying top top dollar and possibly waiting awhile. I would be careful to get assurances of the level of work first, though--the only thing I've had done by them was to build a new seat frame for a Finn Juhl chair (original was missing) and the specs were significantly off. But that's not an upholstery issue.

You could also try calling area dealers and see who they use, though some may not be willing to disclose that information for whatever reasons.

Third, if you don't mind a drive, check out BK Upholstery outside of Philadelphia. They do a lot of mid-century upholstery and have a Knoll section in their gallery page on their website. There's a really good looking Womb chair in dark gray. I don't have any direct experience with them but I've heard good stuff and they're been around for awhile. I'm pretty sure you can also ship your chair to them too, if you don't mind the added expense.

Thank you! Too bad this is so tough to do in DC.