You must have adequate permissions to change or modify the permission set assigned to an object.
To change or edit the permission set assigned to an object:
If you have not already done so, navigate to the item and open its properties. (You can open properties numerous ways, including by clicking .)
In the item’s properties, select the Permissions tab.
The top of the page displays the following:
Current permissions
Your access level for the item.
Extended permissions
Your extended permissions for the item.
Permission set name
The permission set assigned to the item.
Description
The description of the permission set.
Owner
The owner of the permission set.
The bottom of the page displays the users and groups included in the permission set and the permission levels for each.
To change the permission set assigned to the item, click Select next to Permission set name. In the selection page, select a new permission set and then click OK. For instructions on using the selection page, refer to Finding an item on a selection page.
To modify the permission set assigned to the item, edit the remaining information in the Permissions tab by following the instructions in Editing permissions in the Permissions tab.