Does an employer have to follow its own handbook or personnel policy?
Generally, an employer can change his handbook or personnel policy at any time.
Some state courts have held that a handbook is a contract unless the handbook expressly disclaims itself to be a contract. State laws vary in evaluating whether a handbook is a contract. You should consult your own state’s law to determine if it considers handbooks to be contracts between employers and employees.
However, if an employer applies the policies discriminatorily, such as following the handbook for men but not for women, then it may be evidence of discrimination. The handbook should be evenly applied. If the policies are changed, they should be changed for all employees.