Neighbor Notification Address in San Francisco

[Bradford Li]

I am trying to get my neighbor to sign off on a remodeling job I am going to start. The work requires the owner and occupants of the neighboring property to sign off on my set of floor plans. The tenants are OK with the job but I am having a difficult time obtaining the address of the owners as they do NOT live in San Francisco. I was wondering where I should send the notification letter and floor plans. I read that I need to send to the owners' tax billing address. Does this mean the address the property tax? OR the mailing address of where their property tax bill gets sent to?