This subtitle does not preclude an appointing authority and an employee from agreeing to the: holding in abeyance of a disciplinary action for a period not to exceed 18 months in order to permit an employee to improve conduct or performance; or imposition of a lesser disciplinary action as a final and binding action, not subject to any further review. If an employee fails to appeal a decision in accordance with this subtitle, the employee is considered to have accepted the decision. A failure to decide an appeal in accordance with this subtitle is considered a denial from which an appeal may be made. The parties may agree to waive or extend any time stated in this subtitle. Each party shall make every effort to resolve an appeal at the lowest level possible.