There should be a set screw on the lever handle to remove that so the escutcheon plate slides off.

Thanks for your reply! I don't see a screw on the level handle. The only opening on the handle is the hole circled in red below. What could I be missing here?

Looks like a set screw or a set pin to me. It might be a security screw. Any chance you know the manufacturer?

It could also be a spring-loaded button did you try to press that in?

Yep GN, that was what I meant by set-pin, you just described it better.