§ 304-5.1 Conditions for accepting non-Federal source travel payments.
Agencies may accept payment from a non-Federal source or authorize an employee and/or the employee's spouse to accept payment on the agency's behalf only when—
(a) Agencies have issued the employee (and/or the employee's spouse, when applicable) a travel authorization before the travel begins;
(b) Agencies have determined that the travel is in the interest of the Government;
(c) The travel relates to the employee's official duties; and
(d) The non-Federal source is not disqualified due to a conflict of interest under § 304-5.3.