How do I update the name of a person in apple photos?

Double click on photo , take cursor on the face of the person , tap once in the name field , you can use left and right arrows on the keyboard and change a single alphabet or delete the complete name and once again enter the correct first and last name and click on enter key to save .

In Photos, click on 'People' then click on the same you want to edit. :-)

When you open the People album, you have two ways to rename a person -

• Either click into the text field with the name of the person (below the thumbnail with the face) and enter the new name.
• Or click the thumbnail to open the album for this person. At the top of the album is the name of the person, shown in blue. If you click this name, a dialog will open, where you can rename the person.

If you are running Photos 5 on macOS 10.15 Catalina, you cannot rename a person, while the album of the person is still being updated. If you open the album and see "Updating ...", then you have to wait for the update to finish. Or change the name starting from a photo of the person. But that would be tedious, because you would have to edit the name for each face on each photo individually and it would be easy to miss a face.