I currently have the Family Share Plan 700 on a month to month basis as my contract has expired. However, I now want to upgrade one of my phones. Will I be able to do this and continue using the Family Share Plan or do I need to move up to the new Share Everything plan? The reason I ask is because it will be significantly more expensive to do this. We have five phones on the plan, but two of them are essentially emergency phones and are not used regularly.