Question:
“If a tenant has a lease, they can still give a 30 day notice to end the lease, can’t they?”
Answer:
No, they can’t.
A lease agreement binds a landlord and tenant for a certain time period. Neither has the right to unilaterally end the lease early.
If a tenant breaks a lease, my understanding is that they’re responsible for all lease payments until the end of the lease. However, the landlord must make a good faith effort to re-rent the property, which if successful would release the tenant from making further payments.
In practice, few tenants willingly continue paying the rent through the end of the lease.
However, since I’m not a lawyer, please confirm with your favorite landlord-tenant attorney. If you don’t have one, I can recommend one to you.