How to reexport fbx with meshes modified

Hi, guys, I am just trying to figure out How to reexport FBX with meshes modified on the Unity. I got some problem related normal coordinates and I modified them in unity, and then tried to export FBX ( using "ModelExporter.ExportObject" ) that have meshes modified, but it's not working. is there someone to know how to do it?

here's my code

     GameObject gObj = (GameObject)Selection.activeObject;
     List<Transform> children = new List<Transform>(gObj.transform.GetComponentsInChildren<Transform>());
     bool isUpdated = false;
     foreach( Transform tran in children)
     {
         
         SkinnedMeshRenderer sm = tran.GetComponent<SkinnedMeshRenderer>();
         MeshFilter mf = tran.GetComponent<MeshFilter>();

         if (!sm.Equals(null))
         {
             if (!sm.sharedMesh.Equals(null))
             {
                 sm.sharedMesh = getOutLineNormal(sm.sharedMesh); 
                 isUpdated = true;
             }
         }
         else if(!mf.Equals(null))
         {
             if (!mf.sharedMesh.Equals(null))
             {
                 mf.sharedMesh = getOutLineNormal(mf.sharedMesh);
                 isUpdated = true;
             }
         }  
     }
     if(isUpdated)
     {
         string filelPath = AssetDatabase.GetAssetPath(gObj);
         filelPath = string.Format("{0}\\{1}_1{2}", Path.GetDirectoryName(filelPath), Path.GetFileNameWithoutExtension(filelPath), Path.GetExtension(filelPath));

         ModelExporter.ExportObject(filelPath, Selection.activeObject);

     }