Hi Sagar,
Can you provide a screenshot of how the Prompt window looks when you try to refresh a Webi report in RC?
Also please let us know what is the component being used to pass the date value from the dashboard to Webi report?
If your prompt value contains two words separated by a space then you can use a '+' or '%20'.
Eg: John+Stacy or John%20Stacy
Regards,
Niraj