You must be only teasing us...
On which planet do you live?
You are not re-scheduling your spa appointment, but very serious and hard to get interview with USCIS. Do you know how many people are waiting here for their interview? Do you know how hard is to get USCIS bureacracy to do anything?
I would ONLY re-schedule this interview if it was MAJOR emergency - like somebody's life was dependent on it, urgency life-treatening surgery etc. In my opinion, any work-related activity can be arranged, worked-around and even postponed. Certainly, any vacation related activities....Family visits can wait a little bit....Typically, you recieve enough advance notice from INS.
It is your call - do you like more hussle with citizenship for the benefit of "convinent" scheduling?
Think very carefully about this one.
My two cents...
Good luck to you either way!
P.S.: I'm not a lawyer. I'm not an immigration expert. This is not a legal advice. I'm just an ordinary guy and you are responsible for the actions you take.