Report Service Parameters

You need to get

http://reportserver/reportserver/foldername/reportname for passing parameters

The last command in the url is &rs:Command=Render

You can add some other commands as follows:

&rc:Parameters=Collapsed

This collapses the parameter bar but sends the parameters in the URL in the browser 

&rc:Parameters=true

This shows the parameter bar and is the default 

&rc:Parameters=false

This prevents the parameters from being passed in the browser and expanded 

&rc:toolbar=false

This hides the toolbar 

&rc:format=PDF

This will open up the report as a PDF 

&rs:Format=EXCEL&rc:OmitFormulas=true

This will open the report in Excel 

rs:ClearSession=true

This clears the session state for the user. Used where the caching of the report prevents the designer from seeing their updated report and/or data. * This is a very important parameter to know as more often than not, the report data doesn’t update immediately unless parameters are changed, and your report may show cached data if this is not set. 

&rc:StyleSheet=MyCustomStyle

Note don’t add the .css extension. And this style sheet must be in the folder Program FilesMicrosoft SQL ServerMSSQLReporting ServicesReportServerStyles folder.

Use the HTMLViewer.css as your base template. 

ReportServer Parameters: If you add ?/FolderName/ReportName after the http://servername/reportserver you can run the report.
The same applies if you want to list the reports, then just type ?/FolderName after the http://servername/reportserver.
This is commonly used when the user only has permissions at the folder level, not the root level.

So your URl with Parameters should look like:

https://reportserver/reportserver/foldername/reportname&rs:Command=Render&StartDate=05/05/2008&EndDate=12/05/2008&Comments=True