How to make a concurrent program go into 'Warning'

Hi,

I am using Oracle Reports Builder 10.1.2.0.2.

I have to do a modification in my Oracle report.

When I enter a parameter (employee number), the output file should be generated only if there is data for that employee.

If there is no data for that employee, no output file should be generated ( even a blank file should not be generated ) .

I guess we can do this by making the concurrent program go into 'Warning'. But how to do that ?

Thanks,

Bipin