The words of the Commonwealth Constitution can only be changed by the referendum procedure set out in Section 128 of the Constitution. The procedure requires:
A Bill proposing the change to be passed by the Commonwealth Parliament, or by one House of Parliament twice;
A referendum, or popular vote, in which the proposal is approved by a majority of voters throughout Australia, and by a majority of voters in a majority of States. Since there are six states, the majority needed is four. The Northern Territory and the Australian Capital Territory are not counted as States for this purpose;
Assent to the Bill by the Governor General acting on behalf of the Queen.
Lessen the proportion of a State’s representation in either House of the Commonwealth Parliament (by, for example, changing the rule that each State is equally represented in the Senate);
Lessen the minimum number of representatives from a State in the House of Representatives (currently five);
Alter State boundaries, or affect the provision of the Constitution relating to them.
Formal change to the written text itself.(the referendum procedure)
Legal change to the application of the written text. ( Judicial interpretation by the High Court);
Changing practices outside the written text. (Conventions);
Changing political-constitutional realities that affect the way the Constitution works in practice. (Tied grants);
Political adjustments (Referral of powers).