For a period of two years from the effective date of a court order granting town status to a city making the transition from city status to town status, the town shall not file an annexation notice with the Commission on Local Government pursuant to § 15.2-2907, nor shall it institute an annexation court action against any county. However, the foregoing shall not prohibit the institution of nor require the stay of an annexation proceeding or the filing of an annexation notice for the purpose of implementing an annexation agreement, provided that the extent, terms and conditions of such agreement have been agreed upon by the governing bodies of the county and the town.