Proper process to fill light well in San Francisco

[Bradford Li]

Hello BiggerPockets!

Looking to learn more about the process to remodel my home the way I want to! My property is located in San Francisco's Sunset District. This is a property I helped purchase so my parents can retire comfortably in their desired neighborhood. Sunset homes are humble in size so I am trying to maximize the living space inside.  I have a light well within my home that is attached to my neighbors home. Currently, the light well has my set of windows as well as my neighbors window. 

This is the current floor plan. Imagine the neighbor's window is located at the text "14'-10".

This is the DESIRED floor plan. As you can see, the neighbor still has their window space.

I am hoping to infill/remove the light well so only a small gap exists on the neighbor's side with their window.

The issue is that the home next door is occupied by tenants. I haven't been able to reach the property owners to get their permission to infill the light well. The current tenants are all for the light well infill because it provides them with more privacy as well as removing noise traveling through their window. I casually asked the property manager of the neighboring home but she gave me a quick "No". Seeing as she is NOT the property owner, I wrote a letter to the property owners if we have permission for the light well infill. I asked the property manager if she could forward this letter to the actual owners but the property manager has been unresponsive. I'm not sure if the property manager actually asked the owners for permission which is why I want to get an answer from the owners directly. 

I was wondering what type of actions I can do to achieve the desired floor plan legally. 

• - If I am unable to receive an answer from the property owners, what course of action could I take to have the light well infilled if at all possible (going to court?). 
• - What can I do if the property owners say NO, I can't proceed with the light well infill. What can I do legally inside my own home?

This project has been a bit daunting as I am new to this process. I was also wondering if someone could point me to the documentation or laws where I can learn more about the remodel process in SF as well as the laws I need to abide.

Thanks for looking into this! Really appreciate all the help! =D