The appointing authority may change an employee's workweek schedule, shift, and location as deemed necessary by the appointing authority. Unless the need for changing an employee's workweek schedule, shift or location is of an emergency nature, the appointing authority shall give the employee a seven (7) working day written notice of such change. Whenever an employee requests a change of workweek schedule or shift, approval of such request shall not be unreasonably withheld if a vacancy exists in the classification on a workweek schedule or shift other than that which he/she is then working, provided the employee has sufficient classification seniority and, in the judgment of the appointing authority, is able to adequately perform the duties of the vacancy.