Can an iphone upgrade be done on another family plan line and then work for my phone number?

I am currently using a family plan. My phone is not eligible for an iphone upgrade, but one of the other lines is. Do iphone’s work like regular phones where I can “upgrade” another line and then just transfer my sim card to it and it works for my line? Is there anyway to not upgrade my particular line, but keep the iphone attached to my number?

I want to sell virgin mobile phones in my area, what must be done for this business?

I habe a business and would like to sell virgin mobile phones, what must be done to get in this business?