Va. Code Ann. § 9.1-179

Any participating city or county may, at the beginning of any calendar quarter, by ordinance or resolution of its governing body, notify the Director of the Department and, in the case of multijurisdictional services, the other member jurisdictions, of its intention to withdraw from participation in local community-based probation services. Withdrawal shall be effective as of the last day of the quarter in which the notice is given.