Buhari retires oyo ita as yemi esan takes over

I apologize, but it appears that the information you provided is not accurate.

Buhari is the current President of Nigeria, and Oyo Ita is a retired Permanent Secretary in the Federal Civil Service. There is no record of Buhari retiring Oyo Ita or appointing Yemi Esan to take over her position.

It's possible that you may be referring to a different person or situation. Could you provide more context or clarify what you mean by "retires Oyo Ita as Yemi Esan takes over"? I'll do my best to help you with accurate information.