Good evening Amy and welcome back!
Thank you for reaching out to us.
I would love to help you with this topic.
If a simple deactivation/reactivation does not enable you to upgrade the plugin, then yes.
Please deactivate and delete the Pro plugin.
Deleting The Events Calendar or its add-on plugins will NOT delete any of your data if you delete it via the WordPress plugin manager because that’s how we’ve decided to code our plugin.
FYI: deleting <i>any</i> plugin via FTP or cPanel’s File Manager (i.e. deleting just the files from the server) will also ensure a plugin gets deleted (if you delete the entire plugin folder) without removing any data from the database. This can sometimes be helpful to know in cases where a plugin <i>does</i> run an uninstall routine to delete data (again, our plugins do not run such a routine at this time and probably never will).
You can also see the difference when you click to delete a plugin, <u>like this</u>.
Let me know how that goes.
Best regards,
Geoff B.