SDLP MLA Nichola Mallon has been elected the party's deputy leader.
The North Belfast MLA was endorsed by the SDLP's Parliamentary Assembly Group and will be formally ratified at the party's annual general meeting on 7 October.
Ms Mallon was elected as an MLA in 2016 and served as Belfast's Lord Mayor in 2014 to 2015.
She said she was "delighted to be given the opportunity".
"This is a critical moment for our politics.
"The challenge we all face is to forge a society based on a positive accommodation of difference and diversity."
Congratulations to tireless & fearless Nichola Mallon, new SDLP Deputy Leader , unanimously supported by branches & endorsed by MLA group pic.twitter.com/HhsT1h2Dsy— Claire Hanna (@ClaireHanna) September 12, 2017
Fellow SDLP MLA Claire Hanna congratulated Ms Mallon on her appointment with a post on social media and described her as "tireless and fearless".
SDLP leader Colum Eastwood said Ms Mallon was an "outstanding public servant" with "unyielding compassion and fierce commitment to social justice".
"As we enter a period of immense instability on the island and across this continent, there will be an inevitable shift in politics," he added.
"More than ever, we have to be outward looking, we have to be open to the changes on this island and open to its opportunity. I have given Nichola special responsibility to undertake that work on behalf of the SDLP.
"The party is incredibly proud that Nichola is stepping up to this new leadership role."