You may need to define 'not there', and how you want to control it.
There's the obs-websockets plugin, and things like the t2t2 remote control app (mostly meant for scene switching via tablet or smartphone, as well as some other functions), but we'd need more detail about what exactly you want to be able to do remotely, and how remotely you want to be able to do it (from the same room, from the same building, from the same state, from the same planet).