An authorized representation is a pledge that a specific person (proxy) has the right to conduct legal acts on behalf of someone else. The authorized representation may, for example, hold that the person who has received the authorization has the right to enter into contracts that bind the principal (the person behind the authorization).
A valid letter of authorization must, be signed by the principal, name the authorized representative and describe what the authorized representative may do. The authorization should also regulate how long the authorization is valid and how it can be revoked.
When receiving a letter of authorization from someone who shows that they have the right to represent a person or a company, it need to be assessed whether the authorization is valid and whether it really gives the authorized person the powers they claim. One step in this is to assess whether the principal who issued the letter of authorization from the beginning has the authority to conduct the legal act on their own.