The appointing authority may reassign a qualified employee from a position to another position of equal grade and service under the provisions in State Personnel and Pensions Article, §7-602, Annotated Code of Maryland. An involuntary reassignment that may necessitate a change of residence for more than 6 months may be made only upon the review and approval of the head of the principal unit. This is not applicable to classifications or positions requiring Statewide availability as a condition of employment.