An employee's appeal shall be cancelled and the employee so notified in writing in the following circumstances:

1. (a) On receipt of the employee's written request for cancellation.

2. (b) On failure to prosecute, when the employee or the designated representative does not furnish requested information, or proceed with the advancement of the appeal.

   The Office may at its discretion reopen a cancelled appeal on a showing that circumstances beyond the control of the employee prevented pursuing the appeal.