Release of Commercial Tenant California

[Khaled Seirafi]

Hi all,

I have a commercial tenant who's been leasing a space in our building (in CA) for his deli/liquor store for 25 years. Over the past 5 years, we've renewed, updated, and remodeled the building to attract better quality tenants (we have 5 residential units upstairs and another commercial unit). The deli/liquor store lease is up in September 2018 and we don't want to renew their lease, nor do we want to allow the tenants to sell the business to someone else. 

I haven't notified them of our intent yet, but will be doing so soon. What's the best plan of action to take to ensure that all goes smoothly? And how long before the expiration of the lease should I notify them? 

Thanks!