The phrase "an unofficial representative" is correct and usable in written English.
It can be used to describe someone who acts on behalf of a group or organization without formal authorization.
Example: "Although he is not a member of the board, he often serves as an unofficial representative at community events."
Alternatives: "a non-official delegate" or "an informal spokesperson."
In describing the meetings in Washington last week, a State Department official said that as an unofficial representative of the Supreme Council, Imam Husainy had probably represented the most theocratically oriented wing among seven Shiite clerics from the United States and Canada who were invited.
The Vatican has maintained an unofficial representative here for more than 60 years, but only in 1979 was he accorded diplomatic privileges.
As concerned the question of the recognition of the Mussolini government, the Caudillo emphasized-just as previously in the conference of October 5-the Spanish Government was ready to receive an unofficial representative.
He is one of the few Europeans in Northern Rhodesia who support the African nationalist point of view, which he acquired in the course of many years' service as an unofficial representative for African interests in the Northern Rhodesia Legislative Council.
The word "ambassador" can mean an unofficial representative for a good cause.
I feel like I'm an unofficial representative for the band, and it is great!
Among the five taken off the list Friday were Abdul Satar Paktin, a former deputy health minister; Abdul Salam Zaeef, a former Taliban ambassador to Pakistan and a former deputy minister of mines; and Abdul Hakim Mujahed Awrang, a former unofficial representative to the United Nations.
An entry dated 9 December 2013 says: "The Israel State Archives holds a document (not released for publication) showing that Mandela (under an assumed identity) met with an unofficial Israel representative in Ethiopia as early as 1962 … The Israeli representative was not aware of Mandela's true identity.
With the reopening of the embassy in Cuba, there are now just three countries in the world that either do not have U.S. embassies at all, or are not covered by an embassy in a neighboring country or an unofficial diplomatic representative.
Snoop Dogg, the world-renowned entertainment icon and unofficial representative of all things weed, launched Merry Jane, a pot-flavored lifestyle media platform at Disrupt SF. 11.
An article in Scientific Monthly in 1946 called him the "unofficial representative and interpreter of India to the United States".
