I am looking at getting the wife a new iPhone for Christmas (she has a 4, but complains it is slow on IOS7 - I agree).

I will be getting it on a contract through my father's business (they have a great corporate deal with Vodafone). Obviously, she would like to keep her existing number.

iPhone4 has a micro-sim, new iphones have a Nano.

She is currently on Telecom, I am looking at porting her back to Vodafone (she has an 021 number).

What would be the best way to do this, so that she doesn't lose connectivity with family on Christmas day?
Way I see it happening, I will get new phone and new sim with new number this week sometime.

 

Will I be able to call anyone at Vodafone on Xmas day (or Xmas eve I suppose) and port her existing number away from telecom and onto her new Vodafone plan?

Or, will she just have to look at her new phone (or use it with some unknown number) for a couple of days until I can talk to someone at Vodafone?