A sending agency in this State may, in accordance with the travel regulations of such agency, pay the travel expenses of employees assigned to a receiving agency on either a detail or leave basis, but shall not pay the travel expenses of such employees incurred in connection with their work assignments at the receiving agency. During the period of assignment, the sending agency may pay a per diem allowance to the employee on assignment or detail.
Okla. Stat. tit. 74, § 1255