Membership
Some charities have members; some do not. The difference determines who appoints trustees and who must approve constitutional changes.
Trusts have no members. A foundation-model CIO has a membership identical to its trustees. An association-model CIO or a company limited by guarantee has a wider membership that elects the board.
Check which model you actually have before planning an AGM or a vote — see member and members and general meetings. Charities regularly discover mid-dispute that their constitution says something different from what everyone assumed.