Export shared calendar from office 365

Define "shared calendar"? A Calendar in a shared/user mailbox? A Calendar in a Group mailbox? A Public folder Calendar? In any case, if you can access the "shared calendar" in Outlook, you can use the built-in export functionality.

If you are a .Net programmer, you can also query (instead of export) calendars: https://www.emoreau.com/Entries/Articles/2018/05/A-Net-application-to-extract-appointments-from-Office-365-public-calendars.aspx

I have full access to shared mailbox, now I would like to export calendar from that shared mailbox. I already have access to that shared mailbox from outlook 2016. But I cannot export that shared mailbox's calendar. I can export the user mailbox calendar without any issues.