It used to be, for Roman Catholics, that if All Souls day is on a Sunday, it gets celebrated on Monday.
https://www.thebostonpilot.com/article.php?ID=201164
All Saints is a churchwide holy day of obligation and normally celebrated on Nov. 1. If the first day of November falls on a Saturday or Monday, at least in the United States, the obligation to attend Mass is abrogated. All Souls’ Day takes place on Nov. 2, unless it falls on a Sunday, then the celebration is held Nov. 3.