Most lease agreements (for an apartment - residential; or for space - commercial) contain a clause specifically addressing the right to assign the lease.
Use your favorite internet search engine and locate a lease agreement. Find the clause dealing with assignment of the lease and answer these questions about that clause:
1. What is the URL for the lease that you found?
2. What does the assignment clause say?
3. What would happen under the contract if the lessee assigned the lease?
4. What would happen under the common law if the lessee assigned the lease? (Hint: You might need to do a bit of additional research to answer this one.)