From the Content Type List screen:
Locate the content type that requires a name change.
Click on its respective operations menu to open the menu.
Click on the Edit link.
You will enter the content type definition screen.
This screen contains an assortment of different, general configurations that globally apply to this particular content type.
Name text field = change the name.
Description text area field = optionally, change the description as appropriate.
Click the Save Content Type button.
You'll be returned to the Content Type List screen.
A confirmation message will appear at the top of the screen.