Note: When you give a delegate the permissions to accept meetings on their behalf, this also allows that user to send email on their behalf. Please use this permission accordingly.
Windows:
Click the File tab.
Click Account Settings , and then click Delegate Access .
Click the name of the delegate for whom you want to change permissions, then click Permissions .
To change calendar permissions specifically, click on the Calendar drop down and select editor.
To send a message to notify the delegate of the changed permissions, select the Automatically send a message to delegate summarizing these permissions check box.
Select the calendar icon in the bottom left.
In the navigation pane, click the calendar that you want to change.
In the Organize tab, in Calendar, click Calendar Permissions.
Click the name of the person for which you want to change the permissions.
In the Permission Level list, choose the access level that you want. Individual permission levels are automatically filled in below based on your selection in the list.