If a table has an associated partition scheme, you can use this dialog box to choose which column(s) the partition function is applied to. For the function to work, the data type of the column you switch to must be the same as the data type of the column defined in the partition function.
For more information on partition schemes and functions see SQL Server Books Online.
Shows the data types of the columns defined in the partition scheme.
Provides a drop-down list where you can choose the column to apply the partition function to.