Default values for a Report

Hello All,

I have a report where i need to implement the following value (Default) for the date prompts.

Start Date -  Current DateTime

End Date  -  Current DateTime + 3 Months

Currently i have "Start Date" and "End Date" as the prompts but these "Start Date" & "End date" are not being used in the Query filters.No idea from where these "Start Date" and "End Date" are coming from.

We are manually selecting the "Start Date" and "End date" from the Date Picker in the runtime\While refreshing the report.

How to change these Start Date and End date to the default values as shown above.

Sandy