If your commercial tenant does not vacate following the expiration of the lease, do not accept rent from the tenant beyond the lease term. You would then proceed with an unlawful detainer lawsuit without then necessity of serving a 3-day notice.
The information presented here is general in nature and is not intended, nor should be construed, as legal advice. This posting does not create any attorney-client relationship with the author (who is only admitted to practice law in the State of California). For specific advice about your particular situation, consult your own attorney.
I disagree with my colleague. You are extremely well-served by serving a three-day notice and a 30-day notice, regardless of the lease provision.
Responses to Avvo questions are based on a general discussion of the law and in no way constitute legal advice. No attorney-client relationship is created, and you should not take or fail to take actions based on my answers. Consult an attorney in your area. Time is often of the essence. Act quickly!