Does anybody have any experience of rescheduling a CR-1 interview or know how easy it is to do,if at all?

I have been given my date for the 15th November.I am now in the states as I entered on the K3.

Finances and personal commitments dictate that a later date would be more suitable to travel back for.I have emailed the London embassy today but am interested to hear any further information on the matter.

any help much appreciated as always!!

vern.