Section 11. If the district boundary of the regional planning and economic development district established in accordance with section nine includes a majority of cities and towns organized as a regional planning district pursuant to this chapter, said regional planning district shall be dissolved upon the organization of a regional planning and economic development district.

When the Southeastern Massachusetts Regional Planning District is dissolved and a successor district is established in accordance with the provisions of section nine, the jurisdiction and responsibility of said Southeastern Massachusetts Regional Planning District shall be transferred to the successor district and commission and all records, reports, studies, documents, plans and property including all assets and liabilities of said district or commission shall be transferred forthwith to the custody, control and responsibility of the regional planning and economic development commission. Upon the effective date of any such dissolution, all of the permanent or temporary employees of such district or commission shall be transferred to the regional planning and economic development district without impairment of retirement rights and without reduction in compensation or salary grade; provided, however, that nothing in this section shall be construed to confer upon any employee any tenure of office or employment or any rights not held prior to such transfer. The adopted plans and policies of said district so dissolved pertaining to regional planning considerations shall be deemed to be and shall continue to have full force and effect until modified by the commission of the successor district. No such dissolution of a previously established district and no establishment of a district in accordance with section nine shall become effective except in compliance with the following procedure: upon receipt of notification from the director of economic development that he intends to establish a district in accordance with section nine, the city manager in a city having a city manager and the mayor in any other city, the board of selectmen, and the planning board of each city and town therein shall not later than twenty days from the date of notification appoint or designate the respective commission members to serve in the interim period until March thirty-first next, provided, however, that in the case of a planning board which had previously appointed a member of a regional planning commission established in accordance with this chapter, each such planning board shall appoint the same member to the commission established in accordance with section nine for said interim period if said member is willing to accept said appointment, but shall otherwise appoint in accordance with this section. The commission members so designated shall not later than thirty-five days from the date of said notification, elect officers in accordance with section fifteen. Upon receipt of notification from the commission so established, that there has been compliance with the foregoing procedures, the director of economic development shall forthwith notify the state secretary who shall issue a certificate of organization to said district which shall be conclusive evidence of the establishment and organization of said district, and, the director of economic development shall forthwith dissolve the previously established regional planning district.