If you create a list by selecting one of the built-in types ( Christmas, Thanksgiving, Easter General, Wedding, Baby Shower or Birthday), you can still rename it later. This can be useful to create new types e.g. party invitation list etc. It can also be very useful to create groups of say Christmas lists – for work colleagues, neighbours etc.
If you are running iOS 13 or later, there are 2 ways to do this. The easiest is to do a long press on the list to be changed, and select Rename List from the menu.
On the next screen type in the desired name. You can change the year as well – or make the year blank.
If you are running an older version of the iOS, then the list name can be changed, as follows.
Tap on the Edit button (top-left) , then the list name itself. You will then see the screen below.
Just type the desired name in the textbox at the top (“Xmas Work” in this case), and hit Save.
You could also change the list type or year from here, but that would be “unusual” – probably just if you made a mistake in the first place.