Carver schools will undergo major transitions in March with the addition of a new Middle High School principal and the earlier-than-expected retirement of Superintendent Elizabeth A. Sorrell.

Sorrell, who earlier had said she would retire at the of the school year, moved up the date to March recently, after the district won the final approval it needed to build a new elementary school.

Her decision also coincided with the hiring of Janelle Clarke-Holley, a Rhode Island educator. Clarke-Holley is currently a doctoral candidate at Northeastern University and is available to start in March, Sorrell said.

Clarke-Holley will replace principal Scott Knief, who has been named as Sorrell’s replacement.

“I think it’s the perfect time to go. They have great leadership in place,’’ Sorrell said in an interview. “The main story is we’re getting a school, and I am indebted to the voters who approved this. It has been a long time in coming.’’

She said the design firm HMFH Architects Inc. is set to start meeting with teachers and administrators on the layouts that will include “learning commons’’ spaces and a book collection room, which will replace traditional narrow hallways and a library.

The building will have two stories and three wings, with a preschool area somewhat separated from the rest of the approximately 750 students in kindergarten to grade 5, she said.

Construction is set to be completed in June 2018, and the demolition of the two current school buildings and the construction of a parking lot will take place during the summer.

It is set to open in September 2018, Sorrell said.