Reschedule Exam option does not work

Hi,

My exam is scheduled to take plase on the next 2 hours but I am experiencing electrical outage on my home, so I tried to use the email confirmation link about the exam to do the reschedule but it does not let me change the date/time it keeps saying that (Changes to this appointment can no longer be made online), so if online is not possible what is the other ways to change the appointment? is there any phone to call ? The process is not clear.

thanks in advance,

Manoel Benicio