Delete model parts from skeletal mesh

I imported an fbx model but it has a part what I want to delete. How can I do it ?
Thanks

I am using MotionBuilder to export as FBX, but there I can delete only materials in the fbx, not the meshes.

You cannot delete a part of a skeletal mesh inside of UE4; You will have to import your skeletal mesh into a external modeling program (3ds Max, Blender, etc.) where you can delete the unwanted part of your mesh and then re-export it into UE4.

I am not too familiar with MotionBuilder or how it works, but I think I have a general idea of how it works. I just wanted to clear some things first, I’m assuming you have a skeletal mesh that you are trying to animate in MotionBuilder but there is a part of the mesh that you don’t want? Can you import a mesh to MotionBuilder? also could you send me exported fbx?

No, I have an animated model and I want to remove a part.
Example: I want to remove the hair mesh from a human animated model.