Yes you can
Many people reschedule fingerprinting . it is not very uncommon.
It can be preponed. I got a letter to appear for FP in Houston,TX on Dec 28,2001. But I was in some other place. So I took the notice to local INS office somewhere during first week of December and got it done. It all depends on the local office. Advancing FP does not cause any delay.
YOu have to send reschedule form. Instructions are return at the bottom of FP notice. They do not reschedule over phone.
Your approval is not based on your FP date. However late FP can delay approval because when officer picks up your case , if he does not find your FP details he will send it to different area called backlog shelf (or somethng like that). Sometimes it remains there only for long time till you call IIO and he finds out about it.
