It would help everyone if all the months had 28 days. The extra days could be gathered into a new month, which I propose be named Mcdonnella. The new month could be slipped in anywhere except during winter. Winter is long enough. There are 29 extra days, so one of them should be made December 29 so as to mess up things as little as possible.
Changes to the calendar are not unprecedented. In 1582, Pope Gregory changed the calendar to get Easter back to Spring where it belonged. We call his reform the Gregorian calendar. I plan to ask Pope Francis to help with my project. We'll call it the Francescan calendar as a way of saying thanks. There's a February 29th every four years, which could also screw things up, so it will become the last day of the year when it occurs. I suggest it be named "Teresa Day," in honor of my dear wife. That would really set her up for the new year.
Libera in toto orbe terrarum meum novum fastis*
*Deliver my new calendar to all the world.