Set child position and move parents with

Hello, I'm creating a game and I have a problem. I have a gameObject with a rigidbody and some script. This gameObject has 2 child and each child has a collider (trigger). In a script I need to set the position and the rotation of the child and I want that the parent come with the child so the global structure stay the same. I tried with a the localPosition but nothing work. Do you get any idea? Thanks