Hi,
My name is Igor. It's a pleasure for me to help others and I'll try to help you. I am merely a fellow user trying to provide insight and information that may be helpful to others.
It is not possible to update 32-bit version to 64-bit one. You may just install Windows 10 64-bit. If your old Windows 10 was preinstalled by laptop manufacturer, new installation will use the product key stored in BIOS.