Hello! To change a person's name, first click on them. A sidebar appears with buttons to add family members or partners. Above these buttons, information such as birth and death dates, gender and names are displayed. Click on the button "Edit [first name]'s details" and you'll be able to change names, as well as life dates or gender.
If you do not see names, life dates and gender in the sidebar but a list of the person's partners, contact data or facts from their biography, look above the information and below "Add picture", "Show relationship to ..." or "Invite ..." and select the tab "Personal".
Hope this helps!
