Refresh the report.

In Crystal 8.5:

Select Refresh Data from the Report drop down menu, on the top menu bar

OR

Select the Lightening bolt button on the top tool bar menu.

In Crystal XI:

Select Refresh Report Data from the Report drop down menu, on the top menu bar

OR

Select the over under arrows button in the top toolbar menu

Note: If refreshing the report does not result in a parameter prompt then the parameter may need to be re-created.