Hi,
If you are changing your encryption certificate, you will need to rerun the claims authentication wizard. You will probably want to rerun through the IFD wizard as well (keeping all the inputs the same) to regenerate the IFD federation metadata since I believe
that the encryption cert info is also in the IFD federation metadata.
If you have your ADFS setup to monitor your federation metadata endpoints, ADFS should pick up the changes as part of its regular polling interval.
If you are also using this certificate for your SSL binding, you might need to change the IFD inputs to fulfill the cert CN. If this is the case, you will also need to make DNS changes.
Thanks,
Michael