Question: When did they change the australian national anthem?

Disambiguated questions and answers:
context: "Advance Australia Fair", with modified lyrics from the original (see development of lyrics), was adopted as the Australian national anthem on 19 April 1984 by a proclamation by the Governor-General, Sir Ninian Stephen, on a recommendation by the Labor government of Bob Hawke. "God Save the Queen", now known as the royal anthem, continues to be played alongside the Australian national anthem at public engagements in Australia that are attended by the Queen or members of the Royal Family.
question: When did they officially change the australian national anthem to a modified version of "Advance Australia Fair"?
short_answers: 19 April 1984
wikipage: Advance Australia Fair
context: In January 1976 the Fraser government reinstated "God Save the Queen" for royal, vice-regal, defence and loyal toast occasions as well as making plans to conduct a national poll to find a song for use on ceremonial occasions when it was desired to mark a separate Australian identity. This was conducted as a plebiscite to choose the National Song, held as an optional additional question in the 1977 referendum on various issues. "Advance Australia Fair" received 43.29% of the vote, defeating the three alternatives, "Waltzing Matilda" (28.28%), "Song of Australia" (9.65%) and the existing national anthem, "God Save the Queen" (18.78%).
question: When did they reinstate "God Save the Queen" as the australian national anthem for ceremonial occasions?
short_answers: January 1976
wikipage: Advance Australia Fair
context: In 1974 the Whitlam government then performed a nationwide opinion survey to determine the song to be sung on occasions of national significance. Conducted through the Australian Bureau of Statistics, it polled 60,000 people nationally. "Advance Australia Fair" was chosen and was enshrined as the national song, to be used on all occasions excepting those of a specifically regal nature. A spokesman for the Prime Minister Gough Whitlam stated that the Government regarded the tune primarily as the national anthem. During the 1975 election campaign following the dismissal of Whitlam by Sir John Kerr, it was proposed by David Combe that the song be played at the start of the Labor Party's official campaign launch on 24 November 1975 at Festival Hall, Melbourne. Whitlam's speechwriter Graham Freudenberg rejected this idea, on two grounds, one of which was that the status of the anthem was still tentative.
question: When did they first conduct a national survey regarding changing the australian national anthem to "Advance Australia Fair"?
short_answers: 1974
wikipage: Advance Australia Fair
context: No context provided
question: When did they conduct a formal vote regarding changing the australian national anthem to "Advance Australia Fair"?
short_answers: 21 May 1977

Long-form answers:
long_answer: In 1974 a national survey was conducted to change the Australian National Anthem to "Advance Australia Fair". In January 1976 the Fraser government reinstated "God Save the Queen" for royal, vice-regal, defense and loyal toast occasions as well as making plans to conduct a national poll to find a song for use on ceremonial occasions when it was desired to mark a separate Australian identity. On 21 May 1977, a formal vote was conducted to make the change. And on 19 April 1984 "Advance Australia Fair", with modified lyrics from the original, was adopted as the Australian national anthem.