Article 19 1. If the post of head of the mission is vacant, or if the head of the mission is unable to perform his functions a chargé d’affaires ad interim shall act provisionally as head of the mission. The name of the chargé d’affaires ad interim shall be notified, either by the head of the mission or, in case he is unable to do so, by the Ministry for Foreign Affairs of the sending State to the Ministry for Foreign Affairs of the receiving State or such other ministry as may be agreed. 2. In cases where no member of the diplomatic staff of the mission is present in the receiving State, a member of the administrative and technical staff may, with the consent of the receiving State, be designated by the sending State to be in charge of the current administrative affairs of the mission. Article 20 The mission and its head shall have the right to use the flag and emblem of the sending State on the premises of the mission, including the residence of the head of the mission, and on his means of transport. Article 21 1. The receiving State shall either facilitate the acquisition on its territory, in accordance with its laws, by the sending State of premises necessary for its mission or assist the latter in obtaining accommodation in some other way. 2. It shall also, where necessary, assist missions in obtaining suitable accommodation for their members. Article 22 1. The premises of the mission shall be inviolable. The agents of the receiving State may not enter them, except with the consent of the head of the mission. 2. The receiving State is under a special duty to take all appropriate steps to protect the premises of the mission against any intrusion or damage and to prevent any disturbance of the peace of the mission or impairment of its dignity. 3. The premises of the mission, their furnishings and other property thereon and the means of transport of the mission shall be immune from search, requisition, attachment or execution. Article 23 1. The sending State and the head of the mission shall be exempt from all national, regional or municipal dues and taxes in respect of the premises of the mission, whether owned or leased, other than such as represent payment for specific services rendered. 7