Tánaiste Leo Varadkar will take over the position of Taoiseach from Micheál Martin on Saturday 17 December.
The rotation of the Taoiseach's office was agreed when the Coalition was formed in June 2020.
The Programme for Government had specified that the changeover date would be 15 December 2022.
It is understood this has been changed in order to allow Mr Martin participate in the final EU leaders' summit of the year.
It means that the Dáil will sit on Saturday 17 December to vote in Mr Varadkar as Taoiseach.
The rotation will coincide with a wider Cabinet reshuffle, which the three Coalition leaders will discuss in the coming weeks.
It is known that Minister for Finance Paschal Donohoe will change places with Minister for Public Expenditure Michael McGrath.
It is currently unclear what ministerial brief Mr Martin will seek to fill when he leaves the Taoiseach's office to become Tánaiste.
Mr Martin has said that Minister for Housing Darragh O'Brien will remain in his portfolio.
Mr Varadkar will vacate his Department of Enterprise position, but it is not known who will take that role.
The Green Party ministers are not expected to change from their roles in the reshuffle.
SIPO not investigating Varadkar over document leak
Meanwhile, Mr Varadkar has said the Standards in Public Office Commission has told him that it would not be investigating him for any alleged breach of the Standards in Public Office Act or the Ethics Acts, in relation to the disclosure of a confidential Government document to a friend three years ago.
The Tánaiste previously told the Dáil that in April 2019 he gave a copy of an agreement between the State and the Irish Medical Organisation to Maitiú Ó Túathail, whom he described as a friend but "not a close friend".
Mr Varadkar was Taoiseach at the time and Mr Ó Túathail was president of a rival GP organisation, the National Association of General Practitioners.
In 2020, Mr Varadkar apologised for "errors of judgement", but said his legal advice was that he did not commit a criminal offence.
In a statement this afternoon, Mr Varadkar said: "I have been now cleared of criminal wrongdoing and any breach of ethics or standards.
"This is always the outcome I expected".