Upgrade sharing question, what happens BOTH future upgrade dates?

[mryauch]

Here's my situation:

My wife's line has a iPhone 4S with upgrade date of 6/27/13.

My line has a Galaxy Nexus with an upgrade date of 1/12/14.

My Galaxy Nexus's microphone no longer works, thus it's unusable as a phone without using a bluetooth headset that may or may not make me sound like I live in a tin can and/or wind tunnel.

If I transfer her currently available upgrade and use it on my line, how does that affect the dates of upgrades?

A) The "Use The Other Line's Upgrade" Plan - Does her line get renewed for 2 years (upgrade date 9/28/15) and mine stays at 1/12/14?

B) The "Upgrade Date Swap" Scheme - Does her line get my previous upgrade date of 1/12/14 and mine goes to 9/28/15?

C) The "Happy Wife = Happy Life and She's Pissed" Scenario - Are both phones locked until 9/28/15?

I don't want to lock my wife out and prevent her getting an upgrade for 2 years because I couldn't wait a few months.

[tikibar1 · Accepted solution]

A.  If you use your wife's upgrade, her line is the one that receives a new two-year contract and your line is unaffected.

[mryauch]

So if she wanted to then upgrade I would have to share my upgrade back to her line?

[tikibar1]

You wouldn't have to, but if you wanted the first part of C (Happy Wife = Happy Life), then I'd share my upgrade. 

Seriously, yes, she could use your upgrade in Jan. if she needed to.  Otherwise, she has to wait until 9/28/15 (or whenever her new contract is up).