A letter of proxy is a legal letter used to establish a representative relationship between two people. The proxy acts in place of the person she represents, and thus has the same authority and rights. A letter of proxy should be signed and dated by both parties, and may even require an attorney or notary to witness.
A proxy letter can save someone time while still maintaining a presence in the proceedings. It can also allow a person to send someone more knowledgeable of the affairs to act as his proxy, such as an accountant to act as proxy in the case of a financial transaction. Persons who are physically incapable of or find it difficult to travel may also find proxies useful.
A simple, common proxy letter may begin: I, (your name) hereby appoint (proxy's name, position/relationship) of (the proxy's address) to act as my proxy in (the matter in which the person will represent you).