If you need to change an API user, here is a guide.
1. Go to "settings" followed by "users" in the menu on the left side.
2. Select "API access":
3. Select "More'' and then "Edit access" on the small pencil to the right of the user you want to change.
4. Make your changes and then select "Update User".
Get the API documentation here.
NB: Be aware of your GDPR compliance so nobody gets access to data they shouldn't.