The longest serving head of school in Hawaii, is stepping down.

Sister Joan of Arc Souza is leaving Saint Francis School in Manoa after she was asked by the school's overseers in New York to retire. 

She led the school for 27 of its 94 years in existence, taking over in 1991 when it was just an all-girl high school. 

Since then, she has added a preschool, elementary and intermediate schools. In 2006, the school transitioned to a co-ed institution. 

"The decision was made to make a major change now in view of some of the changes that are taking place in the field of education and financing that is needed for the well-being of the school... Everything that we will do has been based on the legacy of Sister Joan of Arc Souza, whose leadership in the school has been not only excellent but outstanding but totally based on Franciscan values," Sister Barbara Jean Donovan, General Minister of the Sisters of St. Francis of the Neumann Communities said. 

The school's board of directors has begun the search for Souza's successor, naming assistant principal Erin Marshall as interim head of school.

Born in Pauoa, Souza graduated from Saint Francis in 1961.