Police officers may trade shifts or substitute tours of duty with another employee without the employer being subject to additional overtime by virtue of one employee working the additional hours during the work period. The following criteria must be met in order for there to be no effect on hours worked:

• Substitution or trading is done voluntarily; and
• The substitution or trading is approved by the employer.

29 U.S.C. § 207 p(3).

The employees’ decision to substitute for each other must be made without any coercion by the employer, and they should be free to refuse the substitution without sanction or explanation. There is no requirement that the employer maintain a record of the time traded or substituted, nor is there any period of time for which the time traded must be paid back by the other employee. 29 C.F.R. § 553.31.