F3 visa interview date- had to cancel

[skyland235]

Hello

I am hoping someone can advise - Does anyone have any idea as to the actual TIME LImit we have to reschdule a new Immigrant visa interview date ? I am guessing that there has to be surely a time limit in which we would need to rescdule? Our prioroty date is current as per this months bulleting and the original date we were given was March 10th ( which we have had to cancel)

thanks