The Planning Board will continue a hearing on June 19 into a proposed upgrade and expansion of New England Executive Park. National Development, which last year purchased the office park off Route 128, wants to overhaul most of the existing buildings in the park and add a 170-room hotel, restaurants, stores, and more office space. The company is asking for three special permits and two minor engineering changes for the project, according to Don Benjamin, the town’s senior planner. Also at the meeting, the board will continue a hearing into a special permit request from National Development to locate a restaurant at 15 South Ave. The site has been used as an overflow parking lot for AMC Burlington Cinema, which is across the street. But the theater recently scaled back its seating by more than half and no longer needs the overflow spaces. Benjamin said that National Development has not yet identified the restaurant that would occupy the site, which it will need to do before the permit can be granted.