I fell like i should know this, but need to double check. I upgraded the 2nd line on my account. I will take the 5S and give line 2 my 5. When the 5S arrives, can I simply take the sim from my 5 and put it in? Then, when ready, put the new sim in the 5 to 'trigger' the activation? (I don't want to disable the current phone on line 2 until i'm ready, but would like to use the 5S when it arrives) Hope that makes sense.