Subject to subsection (b) of this section, if eight or more police employees are assigned to a county or municipal corporation in accordance with an agreement entered into under § 2-602 of this subtitle: the county or municipal corporation shall give the Department at least 5 years’ notice whenever the county or municipal corporation decides to terminate the services of police employees provided under the agreement; and the number of police employees assigned to the county or municipal corporation in accordance with the agreement shall be phased out over 5 years. The Department and county or municipal corporation may modify the manner in which the services of police employees are terminated in an agreement entered into under § 2-602 of this subtitle.