Re-scheduling FP appointment

[Help2008]

Hello all, Can somebody please tell me if USCIS re-schedule FP in a short time?

The fact is that I am waiting for my FP letter (2weeks and 2 days as today) but I haven’t get yet and I need to travel out of country for a period of 3 weeks (no breaking the days allow) next week.

Hopefully I received it during the next week and walk-in for the FP but if not:

It is any problem re-scheduling this FP date? Do I have to call them in advance or just wait until someone here pick my mail, get my letter and then call USCIS?

Any experience with a similar situation?

Thanks.

Aug 07, 2009 Mailed to Lewisville Lockbox
Aug 12, 2009 Package received at Lockbox
Aug 14, 2009 Check Cashed
Aug 14, 2009 NOA – Receipt Number
Aug 19, 2009 LUD - No changes
____---, 2009 FP letter
____---, 2009 FP appt
____---, 2009 IL rec'd
____---, 20?? Interview date
____---, 20?? Oath Date

 

[sarrebal]

You can walk in even after your scheduled appointment, usually on an appointed day (at my ASC was Wednesdays) for almost 3 months after.
My FP appointment was for Aug 20 but the letter said that I could go on every Wednesday until Nov 12.
So no need to reschedule.

 

[Help2008]

Thanks Sarrebal for the answer.