Do you have another device to activate on iPhone 4S line (Line B with the 2 GB plan)? Once you activate another device on "Line B", the iphone 4S is now deactivated. You can then activate the iphone 4S on your line (Line A with the iphone 4) as a "Bring Your Own Device" phone. This will not affect your unlimited data plan on "Line A". Your iPhone 4 should be turned off and deactivated now.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
