Upgrade Transfer - does it add two years JUST to one line?

[CMaker]

I was looking at having my mother (the main line on our family plan) transfer her upgrade over to my line and then I will give her mine next month.

My question is, if I use her upgrade and get a 2-year plan, would that add 2 years to anyone else on the plan, or just her? She is under the impression that it might also effect the 3 other lines on the Family Plan.

Also, this is a random question that I just can't remember, but does a new 2-year plan restart the clock at zero (aka end two years from this new plan purchase date) or tack 2 more years on to whatever the current contract end date is?

Thanks!

[#2]

When you upgrade a phone with a Verizon subsidized price, you have to sign a new 2 year contract.  That contract applies to that phone and line only.  It does not affect any other phones and lines on the account.  It is a new 2 year contract starting with the purchase date of the new phone.  The old contract is cancelled.