ALLIANCE MLA Chris Lyttle has said he plans to stand down from the assembly ahead of the next election.
He has represented his native East Belfast constituency since 2010.
The party has two MLAs in the constituency, the other being Alliance leader Naomi Long.
Mr Lyttle, who was initially co-opted to the assembly when Mrs Long became MP for East Belfast, said serving the constituency had been the "privilege of my life".
"After almost 12 years of service, I feel this is an appropriate time for me to complete my term of office," he said.
"I will be working to achieve as many positive outcomes as possible in the remainder of my term as MLA."
The education committee chairman said he looked forward to supporting his party leader and successor in East Belfast.
Mrs Long described her colleague as a "wonderful MLA", who had "served Alliance and the people of Northern Ireland superbly over the years".
"But more than that, he has been a committed and loyal friend to myself and us all in East Belfast," she said.
"It is sad to lose him on the front-line of politics but I am delighted he is remaining an active member of Alliance in East Belfast, and I look forward to seeing him out on the campaign trail as we seek to deliver the positive change Northern Ireland needs."
