Sarah Ling replaces Virginia McVea on a temporary basis and will hold the role for three months.
Patricia O'Lynn was elected last May but is quitting Stormont politics to take a job at Queen's University.
As it emerges that there will be no Stormont election in December, will one be called in the New Year?
NI Secretary Chris Heaton-Harris says he will give more information next week.
Ten days out from the 28 October deadline, BBC News NI examines the options facing NI secretary.
Chris Heaton-Harris vowed to set an assembly election date if devolution is not restored by 28 October.
Matthew O'Toole has been chosen to lead the party into opposition at the assembly.
Sinn Féin says DUP is preventing other parties in the assembly from working together.
As tensions build over Northern Ireland, concerns of an EU-UK trade war have surfaced.
