Oh, goodness, now you're mixing up canon law and infallibility. Canon law can change. It's human law --- like the rules of order of your own church, the written guidelines or procedures of your board of directors or board of deacons or elders or articles of incorporation or whatever it is.
These things are human rules --- not identical to Divine Law. Everybody knows that.
It's human law --- Yeah...
Them Bad Popes changed a LOT of 'human law'.
Why do you Catholics ALLOW 'human law' to infiltrate your beloved church in the first place?