Take the reins.
Take the reins.
To take the reins" means to assume control or leadership of a situation, just as a rider takes the reins to direct a horse. It implies not just holding the position but actively guiding and controlling the direction and pace at which things happen.
When the manager retired, it was time for her to take the reins of the company.
When the manager retired, she assumed control of the company.
John took the reins of the project after the lead developer moved on.
John took over the project after the lead developer left.
Taking the reins in a crisis is necessary, and she was ready to steer the team through tough times.
She was prepared to lead the team through difficult times during a crisis.