A Ballymena councillor is to take the DUP's Ian Paisley junior's seat in the assembly following his victory in the general election in May.
Paul Frew is expected to replace the new DUP MP for North Antrim later this month before the summer recess.
Under Northern Ireland assembly rules if a member steps down, their party is able to nominate a new person to take their seat.
Last month, Mr Paisley said he would stand down from assembly in June.
He said he had written to party colleagues to inform them of his decision.