Township residents can petition to have a portion of the township become part of another township. If the petition is successful (meets the minimum number of signatures and any state/local requirements for language, format, etc.) then it must be approved by both township boards involved. Because we are talking about a charter township, there may be additional requirements in the charter for this process, so the charter must be throughly reviewed prior to developing the petition. Depending on the nature of the proposed change, the State may have to approve also. I worked very closely on a similar request several years ago where part of a city wished to detach from the city into the neighboring township. There were many issues involved that needed to be addressed including police and fire protection, taxation, infrastructure debt, etc. that you would also need to determine as part of your process. From my experience, I can tell you that this is a long, complex process that requires professional assistance to make sure it is done properly from a legal perspective. I would stongly recommend that if a group of residents is serious about making this change and has enough community support to take this action, then they should secure an attorney well versed in municipal law to assist with this process to ensure it is conducted in a thorough manner that will adhear to all statuatory requirements and hold up to any potential legal challenges. In regards to your second question, it usually is much easier (and more common) for a city or village to annex land than it is to detach land.