What effective date should be used if we want a new plan name to be effective 01-Jan-2013?

We are changing the name of an existing medical plan, nothing else will change. We would like the new name to display and be effective on 01-Jan-2013. Employee's will be able to select the new plan name during Open Enrollment in November 2012. We would like current participants in the plan where the name will change to automatically rollover into the plan with the new name.

For example: We are changing Medical Plan II to New Medical Plan effective 01-Jan-2013

Employee A is in Medical Plan II, Employee A should automatically rollover to New Medical Plan  effective 01-Jan-2013 is Employee A does not make any changes to their elections.