Diplomatic accreditation

Diplomatic accreditation is the process in which an ambassador is certified as one country's official representative to another.Accreditation occurs when a new ambassador presents "letters of credence", or credentials, to the host country's head of state. Letters of credence, which are signed by the ambassador's own head of state, confirm that the ambassador is authorised to represent his or her country, and ask that the host country respect this fact. The presentation of letters of credence is often an elaborate ceremony, and serves as an official welcome to the new ambassador.
See more at Wikipedia.org...