An ECHO unit shall be removed from the premises upon the death of the dependent occupant for whom permitted, unless the other occupant (if there be such) and the resident in the principal dwelling specifically request from the Land Use Board a continuation of the permit; or upon a permanent change of residence of the said occupant or occupants. Removal shall be completed within 90 days of such event. The site shall be restored, such that no visible evidence of the unit remains.