Duplex: Owner-Occupy Unpermitted Garage Studio & ADU Conversion?

[Anne Sweens]

I'm interested in a duplex (zoned R1V2) in Los Angeles (near the beach). One of the tenant's leases includes the use of a backyard unpermitted garage studio. I'd like to legally convert it to an ADU (which I hope is feasible). Upon purchase, I'd like to owner-occupy this unpermitted studio. However, do I have any rights to do so since the tenant's lease includes this studio? Or would I have to first get ADU approval in order to "reclaim" that area? Their rent is significantly higher than the other tenant's since they have access to this additional space. I haven't been able to find any guidance on this so far, so any information would be much appreciated. Thanks!