How does the Thanksgiving date change from year to year?

the reason The date of Thanksgiving changes is because the wasy the day is set. Because thnaksgiving is on the fourth thursday of each November, the date will change because the day does not. Like a birthday for example. your birthday might be on a monday this year but a Wednesday next year or the year after. this is because its always the same date. Same thing with thanksgiving but the other way around. thanksgivings day does not change ( the fourth thursday in November) but the date does

Hope i helped!!