Hang up their shingle - Idioms by The Free Dictionary
hang up (one's) shingle (redirected from hang up their shingle)
hang up (one's) shingle
To start a business of some kind. I'd be glad to take on your case—after years at that law firm, I'm finally hanging up my shingle.
hang out/up your ˈshingle (American English, informal) start to do business from your home, especially as a doctor or a lawyer: After graduating, he decided to hang out a shingle as a consultant.