Unfortunately, you can't remove the columns. Instead you have to hide the ones you don't want to see. The problem with this is that it leaves gaps in your report. What some people do is create a dataset object with generic column names (Col1, Col2, etc.) and build a report using these generic column names. Then they use a dynamic SQL query which uses aliases to put the data into the generic column names. That way, each adjacent column has data in it (since you create the query on the fly), and you just turn off the unused columns at the end of the report. This prevents having gaps in the report.