(A) A "section 124.34 order" or an order of involuntary disability separation is served on an employee when:
(1) It is personally served upon the employee; or
(2) It is received by the employee at the employee's last known address, by certified mail, return receipt requested; or
(3) It is left at the usual place of residence, or last known address of the affected employee, with an adult residing therein.
(B) If the service by certified mail under paragraph (A)(2) of this rule is returned with an endorsement showing the service was refused or unclaimed, then the "section 124.34 order" or the order of involuntary disability separation may be sent by ordinary mail, evidenced by a certificate of mailing. A "section 124.34 order" or an order of involuntary disability separation issued to an employee under the provisions of this subsection shall be deemed served on the third calendar day after the order is mailed.
(C) Employees shall notify the appointing authority, in writing, of any changes of address throughout their employment. A "section 124.34 order" or an order of involuntary disability separation will not be disaffirmed based upon an appointing authority's failure to serve the employee with a copy of the order where the employee has failed to notify the appointing authority of a change of address and the appointing authority has attempted to serve a copy of the order to the employee's last known address. The burden is on the employee to prove the appointing authority was notified of a change in the employee's address.