Situation:
For many years, a sub-committee has been running a convention in an intergroup. The convention bears the name of the intergroup. The members gradually rotate.
At the intergroup, a new events officer is appointed, one of whose duties is to oversee the convention as chair of the convention sub-committee.
The chair attends the first sub-committee meeting, but the sub-committee makes it clear it does not recognise the authority of the chair and will not let itself be chaired by anyone.
Analysis:
The officer is responsible for delivering a convention. The officer is accountable for the delivery of the convention. The officer must therefore have the authority to deliver the convention. (Concept X.) Practically, this means that, whilst the committee should operate in accordance with Tradition II and Concept XII (group conscience, discussion, vote, and substantial unanimity), the chair must be empowered (a) to run the committee and its activities in an orderly fashion and (b) to have the final say where unanimity is difficult to achieve.
If the chair does not have this power, and committee simply proceeds like a headless beast, the committee will have all of the authority for the convention, but no one is bearing the responsibility and therefore accountability. If something goes wrong, there is no no one person to account for the actions of the sub-committee, and there is no mechanism for the Intergroup, which is acting as the custodian of the AA name and reputation, to intervene and exercise its custodial oversight (through reprimand, redirection, reorganisation, or replacement) to correct the problem.
If the chair were to remain in place, the chair would be in the invidious position of being accountable for the results but without any power to influence those results.
Advice:
Resign, and explain to the Intergroup why.