Quote from Chandler in The One with Princess Consuela
Phoebe: Hey, Mon, was it weird changing your name to Geller Bing? Monica: No. No. It felt nice to acknowledge this. Phoebe: Oh. Where did you go to do it? Monica: Um, the, uh- The Ministry of Names ... Bureau. Chandler: You never did it. Monica: I'm sorry. It's just the idea of being an official Bing. Chandler: Hey. I will have you know that- Ah, who am I kidding? Let's call the kid Geller and let Bing die with me.