Here is a detailed explanation of the withdrawal procedure from a cooperative school district written by the New Hampshire School Boards Association in 2013.
It is short and sweet. You will note that it says:
Breakdown and Analysis of RSA 195:26
1. The withdrawal plan that is submitted to the state board of education
must include all the information listed above, pursuant to RSA 195:26.
Most of this information is straightforward and can be ascertained by the
withdrawal study committee.