Okay guys here's the scope.
Got the phone today, and what I did was swap my original SIM in to the new phone and it works just fine. The new SIM was already in the sim tray, and I made sure I took it out before I fired up the phone. I updated the phone to Windows 8.1 without any problem. Actually, the only real reason I bought another Windows phone is after updating my L920 to 8.1 and really fell in love with WP again.
Anyway, now to important part. Cancelling the new line was no problem. AT&T didn't give me any problem, besides me waiting for about 10 minutes before I could actually speak to someone. Here's the caveat. I don't have any problem with this since I'm not planning on unlocking the phone, but others might want to, and here lies the problem.
The number (new line) have to be active for at least 60 days, if I remember it correctly. So, by cancelling the line right away, I'm pretty much stuck with AT&T on this phone. Again, this is really no big deal for me, as I am already with AT&T with 4 lines, and I don't see changing carrier anyway. Plus, I already have a bunch of unlock phone that I use when I travel overseas.
So, I hope everyone is enjoying their $80.00 awesome phone. I am!
The phone looks brand new by the way. I love the size and weight of the L925 compare to my L920. Although, somehow GLANCE looks better on my L920. Not sure if its because one is LCD and the other is Amoled. Overall it's awesome phone for $80. Well, I paid a total of $114.99 (+$35 tax). Being a CA residence they are taxing as on the full price ($399.99) which sucks, but still a great deal.
Update: I just check the phone counter (dial ##634#), and seems like it's never been use. The counter reads 24 min., it's about the length of call I have with the AT&T customer service. Someone mentioned that the counter cannot be reset, so that's the only reason I'm saying it's never been used. But then again, maybe the factory actually reset it.