How to assign calendar permissions to another user.

Assign Calendar Permissions

Open Outlook
Select Calendar
On the Home tab, select Calendar Permissions
Select the Permissions tab if it is not already selected
Select Add
Type the name of the person you wish to add (e.g, doe, jane). Highlight the name that you want to add
Click the Add button and the user's name will display underlined in the text box to the right
Click Ok
Under Permissions you can set the appropriate permissions for the user (e.g., Reviewer, Author, etc.)
Click OK when you are finished selecting the permissions

Permission Settings

Owner	Create, read, modify, and delete all items, and create subfolders. Can change the permission levels that other people have for the folder.
Publishing Editor	Create, read, modify, and delete all items and create subfolders.
Editor	Create, read, modify, and delete all items.
Publishing Author	Create and read items, create subfolders, and modify and delete items and files that you create. (Does not apply to delegates.)
Author	Create and read items, and modify and delete items and files that you create.
Non-Editing Author	Create and read items s only.
Reviewer	Read items only.
Contributor	Create items only. The contents of the calendar do not display.
Free/Busy Time, Subject, Location	See free/busy time as well as the subject and location of items. Cannot Create Files and can only read this basic information, not the full files.
Free/Busy Time	See free/busy time only.
None	No permission. You cannot open the calendar.