Section 4B. At any time after the expiration of three years from the date on which a law to take effect upon its acceptance by a city or town or a municipality as defined in section four, or is to be effective in such cities, towns or municipalities accepting its provisions, has been accepted in any such city, town or municipality such statute may be revoked in the same manner as it was accepted by such city, town or municipality, but such revocation shall be subject to the following restrictions:

(a) This section shall not apply if such law provides for another manner of revocation.

(b) This section shall not apply to any such law which authorizes, but does not require, acceptance by a city, town or municipality to act.

(c) This section shall not apply to any action taken under chapter thirty-two or thirty-two B.

(d) This section shall not apply to any action taken to establish a regional district, authority or other entity which involves another city, town, municipality, district or other governmental entity.

(e) This section shall not affect any contractual or civil service rights which have come into existence between the city, town or municipality and any officer or employee thereof as a result of the original acceptance of any such law or the provisions thereof; provided, however, that such revocation shall apply to the successor to the incumbent officer or employee, which application shall prevent such contractual or civil service right from automatically continuing with respect to such successor officer or employee.

If a petition signed by five per cent or more of the registered voters of a city or town is filed in the office of the city or town clerk within sixty days following a vote other than a vote taken by voters on an official ballot to revoke the acceptance of any optional provision of the General Laws, requesting that the revoking of such acceptance be submitted as a question to the voters of such city or town, said vote to revoke shall be suspended from taking effect until such question is determined by vote of the registered voters voting thereon at the next regular city or town election, or if the city council or board of selectmen or other authority charged with calling elections shall so direct, at a special election called for that purpose. Petitions filed requesting the placement of the question or revocation on the ballot for determination by the voters shall be substantially in conformity with the provisions of the law governing the signing of nomination papers for city or town officers, as to the identification and certification of names thereon, and submission to the registrars thereof. A brief summary of the relevant section or sections of the General Laws shall also appear on the official ballot. If such revocation is favored by a majority of the voters voting thereon, the acceptance of said optional law shall be revoked and it shall become null and void beginning with the first day of the month next following said vote of revocation. The question to be placed on a ballot shall be essentially as follows:

''Shall the acceptance by ___ (City, Town) of section(s) ___ of chapter ___ of the General Laws be revoked?

YES___ NO___''.

If, on the sixty-first day following the date a vote has been taken to revoke the acceptance of an optional provision of the General Laws, and no petition as aforesaid has been filed, the vote to revoke shall become effective forthwith.

If at the time a city, town, municipality or district is authorized to revoke its acceptance of a law under the provisions of this section and such city, town, municipality or district has adopted a change in charter or otherwise is required to adopt a different procedure for acceptance of such law other than that procedure used for its original acceptance, then the procedure for acceptance in effect at the time of revocation shall be the manner for revoking such original acceptance.