Mother and VCCP are currently in the final pitching stages for the £14m account after Wieden & Kennedy, United London, Leagas Delaney and Miles Calcraft Briginshaw Duffy were knocked out of the running at an earlier stage.
The review was called in April after the directories publisher ended its 23-year relationship with Abbott Mead Vickers BBDO. Conflict with AMV's BT account was cited as the motive for the split.
Francke joined Yell in April 2004. She was previously the strategic marketing officer at Boots, a position she held for just eight months before she was ousted, again in mid pitch, as part of a company restructure.
John Condron, chief executive of Yell, said: "Ann is a very good, smart marketer. She now wants the challenge of running a business of her own and we understand this. She leaves with all our best wishes, as well as our confidence that when she achieves her ambition she will never forget where first to advertise."
Francke said: "Yell is a fantastic business and I have been privileged to be part of it. Looking ahead, though, I want to use all the experience I have gained at blue-chip companies to become responsible for creating the vision and running a business in my own right.
"I have been approached by a number of third parties and reviewing these opportunities is not something that I can do while remaining with Yell. Hence my decision to leave. I very much appreciate Yell's understanding and support. Yell will always hold a special place in my memories."
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