How to export & import Skeletal Mesh between Blender and Unreal

Are you frustrated trying to export a Skeletal Mesh from Unreal Engine to Blender and try to bring it back? Did you get that error: FAILED TO MERGE BONES This could happen if significant hierarchical change has been made - i.e inserting bon bteween nodes Would you like to regenerate Skeleton from this Mesh ? **WARNING: THIS WILL RECOMPRESS ALL ANIMATION DATA AND POTENTIALLY INVALIDATE*** Here is my journey to make that work!