After migrating a Manager and their admin from Lotus Notes to Exchange, there can be some problems experienced with the level of delegate permissions that translate across.
In one case a user on Lotus Notes had "Author" rights which means they have the ability to delete items from their managers calendar. However when they have "Author" access when they are in Outlook, this means that they do not have permission to delete from their managers calendar.
The solution is to apply "Editor" rights to the delegate in Powershell as below:
To view current permission status on a managers account:
get-mailboxfolderpermissions -identity <the managers id>
To view the permission status on a managers folder (in this case the calendar)
get-mailboxfolderpermissions -identity <user>:\calendar
To add a users rights
Add-mailboxfolderpermissions -identity <user>:\calendar -accessrights editor -user <adminusername>
To give the admin "Editor" rights on the managers folder:
set-mailboxfolderpermissions -identity <user>:\calendar -accessrights editor -user <adminusername>
"Editor" rights is just for this example, there are of course other levels of permission available, with "owner" rights being the highest permission available.