Section 4A. At any time after the expiration of three years from the date on which any special act of the general court has been accepted by the voters of a town, and not less than ninety days before the date of an annual meeting, a petition signed by not less than ten per cent of the registered voters of the town may be filed with the selectmen, requesting that the question of revoking the acceptance of any special act be submitted to the voters. Thereupon the selectmen shall cause the question of revocation of the acceptance of such special act to be placed on the ballot at the next annual election. At said election the vote shall be taken in answer to the following question, which shall be placed on the official ballot to be used for the election of town officers:— ”Shall the acceptance by the town of of an act passed by the General Court in the year , being chapter of the acts of , entitled ‘An Act providing in the town of ‘ be revoked?” If such revocation is favored by a majority of the voters voting thereon by ballot, the acceptance of said act shall be revoked and said act shall become null and void beginning with the first day of the month next following said revocation. This section shall not apply in towns having a population in excess of fifteen thousand inhabitants, nor shall it apply to any acceptance by a town authorizing but not requiring it to act in any manner, to any action taken under chapters thirty-one or thirty-two, to any special act in which other provision is made for revocation, to any special act which authorizes the making of a capital outlay or public improvement, nor to any special act involving participation or membership in a district including a regional school district. No revocation of a special act hereunder shall affect in any manner any contractual rights, civil service rights, rights of tenure, or pension or retirement rights arising from the provisions of such special act.