Thank you @Quetzalcodename for you reply, sorry I forgot to upload screenshots 
I made a construction script to set the master pose on all my skeletal meshes, I have (Mesh, Head, Torso, Legs).
Then a custom Event to switch the head gear, which I call it using the Buttons on the widget :
Unfortunately, I don’t get any Error it’s just that nothing happen when I click on the buttons, sorry, as a new user I can’t upload more screenshots