Tripoth,
I don't see Mitel allowing you to do that.
1. You would need to contact Mitel to get the licenses removed from the old CF.
2. You would then need to pay Mitel to go into the existing CF to clear out the license so you can apply the updated one.
3. There is nothing stopping you from saving the old licensing and putting it back in so Mitel may require you to order a new CF and return the old one.
4. You would then need to see if they will allow you to use the now released SIP licenses for a different customer.
Personally, I would say no and most likely Mitel will too.
Thanks,
TE