Is it legal for the secretary to act as the director of the neighborhood Committee when the director resigns?

It is obedient. The resigned director has resigned through formal procedures, and the Secretary-General has the authority and qualification to act as an agent of the Secretary-General, so the post of agent of the Secretary-General is in compliance. The director of the neighborhood committee refers to the main leadership position of the community neighborhood committee, responsible for organizing, coordinating and managing the affairs of the community, and communicating and negotiating with the higher government or other institutions on behalf of the community.