How do I rename branch on the GitHub website?

I just did it without downloading any code to my laptop and using only the GitHub site.
The solution looks the same as @swcool’s, but I want to add about the default branch.
In my case, the name of the renaming branch did not exist.

1. Change the default branch (to the old branch you want to rename)

2. Create a new branch (with a new name)

   This action will copy all the contents of the default branch (the branch with the old name) to the new branch (with a new name). At this time, you have two branches with the same code.

3. Change the default branch (to the new one with a new name)

4. Delete the old branch