How to make Prone collider for 3D?

Hey, so the question is how to make/change collider of the character in the prone position?
For example, for crouch i’m just making the height of the CharacterController smaller, but what i need to do with the Prone? Since character going from vertical position to the horizontal and i can’t change the CharacterController width.

Here’s what i mean:

What i have tried:
Create a second box collider, make it horizontal like character model in the Prone position and set Rigidbody to Kinematic. (In this case this second collider is not colliding with anything, and it looks the same as 3rd case on my picture).

How to make it correctly, guys?