In all Residence Districts, a non-conforming use listed in Use Group 6, 7, 8, 9, 10, 11B, 12, 13, 14 or 15 may be changed, initially or in any subsequent change, only to a conforming use or to a use listed in Use Group 6. In the case of any such change, the limitation on floor area set forth in Section 32-15 (Use Group 6) shall not apply. Eating or drinking establishments with musical entertainment, but not dancing, thus permitted as a change of use, shall be subject to the enclosure provisions of Section 32-411.