Child theme question

How do I update a theme when I use a child theme?

I want to update the main theme “behind” the child theme. Do I have to switch to the main theme and then update the theme? (not good because people will see another website for some time)

Or can I just update the theme as i would normally do with this plugin, and then the plugin will automatically update the main theme behind the child theme?

https://www.ads-software.com/plugins/easy-theme-and-plugin-upgrades/