Change oand update in mass supplier

Hello
I'm look all around.

I can change the builder in mass for my products, but's i can't change any supplier

Example:
i buy a large gamme of tyres form supplier ""MYTYRE""
i'm signed a new contrat from "YOURTYRE" is more cheap to me

The EAN code or UPC code is the same and i wan't work more with MYTYRE

So i want just change the supplier, it's no possible actually