Assignment and sublease: assignment is a complete transfer of tenant’s remaining lease term; sublease is a partial transfer; a lease is

both a contract and a conveyance and these are independent grounds of liability; assignor remains liable on lease through privity of

contract; assignee is liable through privity of estate; sublessor remains liable on both privity of estate and contract; sublessee is not

liable to landlord because neither privity exists; non-assignment and non-sublease clauses are valid but construed narrowly; waiver by the

landlord once is a permanent waiver unless otherwise specified