Simple Powershell script for updating Exchange Online user permissions to a Shared calendar.

Relevant background information: The script assumes you have output a CSV of the Exchange Online (EXO) Users with at minimum a single column for the "Alias" from the EXO server, and it is stored in the same directory as the script.

$user variable assumes each entry has the "Alias" column with a header in your CSV.

It also assumes that you have already logged into ("Connected to") the Exchange Online Management Powershell, more info on that here.

There are now two versions: one that uses "Remove > Add" and a second, more streamlined version that uses "Set" for a single (after CSV import) command solution.