from prmia.org candidate guide:
Please note that all vouchers used to schedule exams have an expiration date. Should you
attempt to schedule or reschedule to a date beyond the expiration date of your voucher, it
will not be accepted by Pearson VUE. You may contact
support@prmia.org for a new
voucher number, which will be provided to you without charge, subject to the condition
that the request is made within one year of the expiration date. After one year has passed
since the expiration date of the voucher, no replacements will be made.