assume the position
1. To take over the role and responsibilities of a particular job. My boss wants me to assume the position of treasurer this year, but I don't know if I want the extra workload.
2. A command issued by US law enforcement officers, meaning to stand with one's back to the officer and hold one's arms in a position to be either handcuffed or frisked. Primarily heard in US, South Africa. I knew I was in trouble when they asked me out of the car, but I knew I was going to jail when they told me to assume the position.