FEI president Princess Haya
In a statement the FEI said that, considering the present situation, Mariette Withages decided to present her resignation.
The FEI Bureau thanked Withages for her good work over the nearly eight years she has been in the role, and for the contribution she has made to the Development of the Dressage sport during this time.
Mariette Withages will present the Dressage Committee report to the General Assembly.
Earlier this month the FEI's president Princess Haya called for the immediate resignation of the entire dressage committee, saying it did not fully represent the interests of the dressage community.
"The FEI Executive Board has taken this decision following a series of issues indicating the current Committee's lack of flexibility on certain key matters," it said in a statement.
"The committee has been seen to work in isolation, not fully representing the interests of the dressage community as a whole," it added.
An Ad Hoc Working Group includeing Frank Kemperman (NED), chairman and representative of the event organisers; Richard Davison (GBR), riders representative; Robert Dover (USA), trainers representative; Alain Francqueville (FRA), chef d'equipe, was to be approved at the general assembly, which ended yesterday.