20 C.F.R. § 10.323

(a) If an employee refuses to submit to or in any way obstructs an examination required by OWCP, including testing such as functional capacity determinations conducted in connection with an OWCP-directed medical examination, his or her right to compensation under the FECA is suspended under 5 U.S.C. 8123(d) until such refusal or obstruction stops. The action of the employee's representative is considered to be the action of the employee for purposes of this section. The employee will forfeit compensation otherwise paid or payable under the FECA for the period of the refusal or obstruction, and any compensation already paid for that period will be declared an overpayment and will be subject to recovery pursuant to 5 U.S.C. 8129.

(b) If the employee does not report for an OWCP-directed examination or in any way obstructs this examination, he or she may provide an explanation to OWCP within 14 days. If this explanation does not establish good cause for the employee's actions, entitlement to compensation will be suspended in accordance with 5 U.S.C. 8123(d). Should the employee subsequently agree to attend the examination or cease the obstruction (as expressed in writing or by telephone documented on Form CA-110), OWCP will restore any periodic benefits to which the employee is entitled when the employee actually reports for and cooperates with the examination. Payment is retroactive to the date the employee agreed to attend or cease obstruction of the examination.