Blackforce

If you see the error message :-

The User has insufficient access right

When trying to delete, move or carry out other operations on a mailbox do the following :

AD Users and Computers
View, Show Advanced
Double click on user
Click Security
Click Advanced
Tick the box include inheritable permissions

To Change a mailbox from one type to another in exchange 2007 and 2010 like below :-

User mailbox to shared mailbox
User mailbox to resource mailbox
Shared mailbox to user mailbox
Shared mailbox to resource mailbox
Resource mailbox to user mailbox
Resource mailbox to shared mailbox

Type the following in the exchange management shell.

Set-Mailbox ConfRoom1 -Type value

Where value is Regular, Room, Equipment, Shared.