Joslin replaces agency founder Nick Fulford, who now becomes chairman.
She said that the agency had decided to part ways with "a number of clients on the books that didn't fit with our ethos, skill set or future ambitions", although she declined to name any of these, and that the business had worked to "refresh its sense of identity".
She said the end result was a client list the agency was "excited to be working with", including shapewear brand Spanx, first aid charity St John's Ambulance, and cosmetic dental surgery The Smile Centre.
Joslin, who handles a team of eight, said the agency is now looking to expand its client portfolio and its team "without losing its identity or the ability to be nimble and flexible".
She joined EdenCancan as a senior account director in 2015 and was promoted to the role of associate director last year. Before this she spent a year as account director at Focus PR, working for alcohol brands including Jim Beam and Courvoisier.
While an account director at PR firm Spreckley Partners, Joslin was also named as one of PRWeek's 30 Under 30 in 2013.
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