I guess you got the answer for a similar question you posted last week here.
"The synchronization group does not have a main unit as such after you have connected them. So you can generate the connection code either on your old phone or your iPad."
Let us know should you have further question.
Don't hesitate to mark Harri_k's reply as solution on the other thread as this might help other member of the community.
Our community is currently not localized in Finnish. Could you repost in English so that the greatest number can assist you with your phone change problem?