The offices of the Commission shall be located, and its public sessions held, in the City of Richmond, and all notices, writs and processes issued by the Commission shall be made returnable to, and command the corporation or person against whom directed to appear before the Commission and answer on a certain day to be named therein; but the Commission may, in its discretion, if public necessity or the convenience of the parties require, hold public sessions elsewhere in the Commonwealth, and may order any notice, writ, or process to be made returnable to the place of any such session; and for the holding of any such session the Commission may occupy the courtroom of the courthouse of the city or county wherein such session may be held, if such courtroom shall not at the time be in use for the sessions of the court of any such city or county.