The principals of Round Hill and Hillsboro elementary schools will trade places in the fall in what Loudoun County school Superintendent William Butt called "constructive changes for the good of the school system." Hillsboro Principal Evalyn Collier, a 28-year veteran of the Loudoun County school system, will go to Round Hill, which has a student population of 140, double that of the Hillsboro school. "I've done a lot of changing in my career," she said. "I'm used to it. Besides I used to attend Round Hill school. I'll be going home."

For Kenny Vance, who has spent the past 20 years at Round Hill, the move will be a wrenching one. "I've had opportunities to make lateral moves before but I passed them up. I was already at the best school in the county." Vance said he plans to spend plenty of time in Hillsboro before September so he "won't be a stranger" when school opens.

One of the events Vance planned to attend was last week's special production of "Peter Pan" performed by the students. The play was so well received two weeks ago, Collier said, that the students and staff agreed to repeat it for 40 retarded and handicapped adults from the Echo facility in Purcellville and 15 senior citizens from Purcellville, Lovettsville and Neersville. "The faculty taught a unit on problems of the handicapped and retarded," Collier said, "and the children are prepared."