step into (someone's) shoes
To fill someone's position, especially one of power or authority. I don't know who they're getting to step into Davidson's shoes, but I doubt they'll be anywhere near as good a manager as he was. I tell you, I wouldn't want to step into her shoes. Sure, the pay would be better, but I don't want all that stress!
step into someone's shoes
Fig. to take over a job or some role from someone. I was prepared to step into the boss's shoes, so there was no disruption when he left for another job. There was no one who could step into Alice's shoes when she left, so everything came to a stop.