There are two ways to remove a column from a report: from within the Displayed Columns configuration tool or using the Remove Column option in the column menu of the report.
Remove a Column from the Displayed Columns Configuration Page
To remove a column from the current report from within the Displayed Columns configuration tool, clear the check box next to that column in the Available Columns list or click the X next to the column in the Current Columns list. If you would like to remove all columns from the report, click the Remove All link above the Current Columns list.
Remove a Column from the Column Menu
Click the column heading of the column you want to remove and select Remove Column.