You can create new user-defined properties for an item by passing a Property object as a method argument. To remove a property from an item, set the property to an empty value. You cannot remove reserved properties. For a list of reserved item properties, see Report Server Item Properties.
If a specified property does not exist when the SetProperties method is called, the property is created and set to the value you supply. If the property already exists, its value is overwritten. Setting an empty value for a property that does not exist has no effect on the item or its properties.
If an error occurs, no properties are set.