No. TREC Rule 535.4(c) states that a person must be licensed as a broker or sales agent to show a property. “Show” includes causing or permitting a property to be viewed by a prospective buyer or tenant, unlocking or providing access onto or into a property for a prospective buyer or tenant, and hosting an open house at the property. As such, an unlicensed assistant must refrain from any activity that allows the buyer to be able to view the home, which includes unlocking doors.