if i upgrade my verizon cell phone to a lg g3 smart phone how can i still use my old lg standard phone as well. just as an eme

[farmerizzy]

can i use my old basic phone after upgrade to new smart phone using same number and carrier . just as emergency back up.

 

[rgd1101]

Only 1 active at a time, you will have to contact your carrier to switch it to another phone.

 

[Someone Somewhere]

If all you want it for is actual emergencies, then you can usually call 911 without an activated SIM, at least on GSM networks. Not so sure about CDMA.

Other option is to just sign up for a cheap pre-pay plan. At a guess, you'd need to top up at least once a year.