"I'll be in late today, Chris, I have to go to a bris." (Glinert)

"Although I don't know about the brit mila for conversion in particular, I would like to add that one of my nephews had medical issue when he was born and the actual circumsion was postponed until he was approx. a year old. But he still had a brit mila ceremony (about 10 days after birth) with an Orthodox Rabbi (Mohel) who explained to everything that that Brit Mila is not only about cutting but also about name giving (as this was when my nephew's "Hebrew" name was formerly announced to everyone)." (source)