If any other school district or districts in the Town of Bradford shall at any time, by their vote at a meeting duly warned for that purpose, signify their desire to become united with the Bradford Academy and Graded School District, and if the Bradford Academy and Graded School District, at a meeting duly warned for that purpose, shall vote to agree to such union, then the additional district or districts shall become and form a part of Bradford Academy and Graded School District; and such union of districts may be made upon such terms in regard to the school property of each as may be mutually agreed upon by the districts. And by vote of the Town of Bradford, and by consent of the Bradford Academy and Graded School District, at any annual or special meeting of the Town and the District, duly warned for that purpose, territory from adjoining districts may be added to the Bradford Academy and Graded School District; or territory may be taken from the Bradford Academy and Graded School District by vote of the town as aforesaid, and by the consent of two-thirds of the voters in the Bradford Academy and Graded School District present at any meeting legally warned for that purpose.