Update mesh vertice coordinate

How to update mesh vertices coordinate after a rotation or applying a quaternion?

Could you provide more information and description about what you do, what you have and what you want to achieve?

I import an stl file to three.js
On mouse click on specific face, the mesh should be aligned to horizental plan.
Firstly, we apply a quaternion to mesh and will be aligned in parallel to plan, but when try to get the Max and Min Z coordinate of the mesh to get the center, we detect that coordinate still the same as before the quaternion applied to mesh