The termination of the lease ends when the lease term expires. However, there are circumstances when the landlord gives the tenant an early termination notice for violating provisions of the lease or for committing an illegal act on the premises.
A notice of Termination of Lease can be given by the landlord to the tenant terminating the lease. This could be used when terminating a month to month lease or termination of a term lease as a result of the tenant violating a lease provision or committing an illegal act on the premises.
If either party violates the lease terms or conducts an illegal act, the lease can be terminated. If the landlord fails to make major repairs, violates city health and/or safety codes, violates any local, state or federal housing discrimination or sexual harassment laws, the tenant can legally terminate the lease and move.
It is best if the parties can negotiate the termination between themselves without involving attorneys and or mediators. If not, then the party that is instituting the termination will need to hire a lawyer.
The landlord can evict the tenant for violating the terms of the lease or committing an illegal act by a legal eviction. The landlord cannot just take it upon himself to throw the tenant out or lock them out. That is illegal.
Unlawful detainer actions are considered eviction lawsuits. The landlord must serve the tenant with a three day notice to pay rent or quit first. If the tenant does not pay the rent, then the landlord can start a formal eviction process by serving the tenant with an unlawful detainer action and filing the action with the eviction court. If the landlord obtains a judgment in the landlord's favor, the court will issue an order that the tenant be immediately evicted and the sheriff will come and evict the tenant.
If a tenant has filed for bankruptcy, the bankruptcy will automatically stay the eviction until the bankruptcy is resolved or the bankruptcy court allows the eviction. Bankruptcy courts are sympathetic to landlords so they will try and lift the stay if the landlord files an action with the bankruptcy court requesting that the stay be lifted so that the landlord can evict the tenant.