Has the date of converting the lunar calendar into the solar calendar been changing? Has the constellation changed with it?

Constellation is unchangeable, because it is based on the solar calendar, which is unchangeable.

There is a lunar calendar on the day of birth, and it is different to change the lunar calendar to the solar calendar every year.

So some people celebrate their birthdays in the solar calendar, and it is that day every year.

People who celebrate their birthdays in the lunar calendar will look for the day of the lunar calendar.

I hope it helps you.