Contract extension with ESN change?

I search the forums and google, but i could not find a clear answer.
Does switching phone extends your contract?
In my experience, Yes it does, but maybe something changed?

I tried to upgrade my phone 2 year after activating my line. But i could not because my contract is not up. Reason why, because i did an esn change, one through insurance (same phone) and one from a different phone. The lady said if the phone were the same she can look through computer and verify it, obviously the second phone was not the same. So it renew my contract and i could not upgrade my phone.
My experience from Verizon is that upgrade date does not change even if contract get extended.
My sister phone is a piece of trash, I believe it's defective issues, white screen, don't receive phone calls. But no water damage and a friend of mines with the same phone has the same problem, but Sprint did not want to switch it out.
My sister brought a new phone and want to switch it, but i want to confirm that it doesn't not extend the contract.
Thanks, sorry about the long post

One thing I would like to add. My friend's contact extended because he sign up for the online Sprint account.(actual reason they told him) WTF?

Did you go to Sprint online and read the fine print?

As far as I know, it should not extent your contract as your not doing anything to the contract itself, you just replacing a defective phone.

I'd call first to verify.

It only extends your contract if you accept the rebate on a new phone. Insurance/warranty claims DO NOT extend your contract!

HA!! Sprint uses ANY reason to extend your contract! -Upgrade, ESN change, to them IS an upgrade, add any features, take any features away....extended contract- 2 new years!!

Not true! I'm an indirect dealer for Sprint Nextel and can say with 110% certainty that this is a false statement. Most customers do not take the time to make sure they are getting what they really want. All you have to do is ask questions

P.S. Please don't post inaccurate info about ANY company.

This is sooo true..even when you call Cust Serv to make a address change (or any change) they'll offer you $70 off your next bill if you extend contract..whether you accept the $70 or not..your contract will start all over. I've seen this happen lots of times. (it happends sometimes..not all the times)
Insurance is the samething..they'll change your upgrade eligibility and if they provide you a different model..more likely that your contract restarted.
If your gonna do some changes write time,date,employee ID#,names, or your screwed.

It was done to me, on 2 separate lines 2 different times, it was done to other people I know as well.

Call the retention dept. they will correct it asap.

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