Subletting vs assigning a lease: which one do you need?
In a sublet, the original tenant commonly remains tied to the primary lease while another person rents from them for a period. In an assignment, the tenant transfers their lease interest to someone else, often subject to lease terms and landlord approval.
The labels are less important than the documents. Read the transfer clause, ask what the landlord requires, and confirm in writing who remains liable for rent, damage, and the lease term. A new occupant may not release the original tenant automatically.
Do not use an informal arrangement to avoid a lease restriction. Get consent if required and make the move-in, move-out, payment, and deposit terms explicit.
Source: California Civil Code, assignment and sublease.