David Goodman, the executive director of the Office of the Chief Rabbi, is to leave after a year-and-a-half.
Chief Rabbinate Trust chairman Peter Sheldon said Mr Goodman "has decided to move on to other things and we reluctantly agreed he can leave. He will be leaving before the end of the year."
There will be no replacement for the former Kisharon Day School executive director, who succeeded Syma Weinberg in the OCR post.
Instead, Paul Fabian - who was formerly in the fashion business and has advised the Chief Rabbi in an honorary capacity for a number of years - will become part-time head of external relations. And the OCR's long-time office manager, Joanna Benarroch, will head community relations for the Chief Rabbi.
"The Chief Rabbi will be adequately served in the numerous roles he undertakes," Mr Sheldon said.