5 C.F.R. § 734.302
(b) Activities prohibited by paragraph (a) of this section include, but are not limited to:
(3) Soliciting, accepting, or receiving uncompensated individual volunteer services from a subordinate for any political purpose.
Example 1:An employee who signs a letter seeking uncompensated volunteer services from individuals may not identify himself or herself by using his or her official title. However, the employee may use a general form of address, such as “The Honorable.”
Example 2:A noncareer member of the Senior Executive Service, or another employee covered by this subpart, may not ask his or her subordinate employees to provide uncompensated individual volunteer services for a political party, partisan political group, or candidate for partisan political office. Moreover, he or she may not accept or receive such services from a subordinate employee who offers to donate them.
Example 3:An employee may not require any person to contribute to a partisan political campaign in order to win a Federal contract:
[61 FR 35100, July 5, 1996]