Tate has stepped down from her day-to-day job to spend more time with her family, but will remain a shareholder in the agency.
It is understood that from September she will work in a consultancy role for a client, although Tate declined to give further information about the role.
The move comes five years after she co-founded Open Road, which specialises in corporate comms, CSR and public affairs. Tate co-founded Open Road with CEO Graham McMillan, chairman Nick DeLuca, and director Martin Le Jeune in January 2007.
Formerly, she was head of public affairs at Spirit Group, having been a director at Fishburn Hedges following eight years at the agency.
PRWeek reported last month that the agency has been called in by Vodafone for a CSR brief. Current clients also include Asda, Prudential, Airwave and Resolution.