As stated in Sec. 778.105, the beginning of the workweek may be changed for an employee or for a group of employees if the change is intended to be permanent and is not designed to evade the overtime requirements of the Act. A change in the workweek necessarily results in a situation in which one or more hours or days fall in both the ``old'' workweek as previously constituted and the ``new'' workweek. Thus, if the workweek in the plant commenced at 7 a.m. on Monday and it is now proposed to begin the workweek at 7 a.m. on Sunday, the hours worked from 7 a.m. Sunday to 7 a.m. Monday will constitute both the last hours of the old workweek and the first hours of the newly established workweek.