Unable to Preview Reports in Landscape Orientation

Hi All,

We are working in WPF application in our application we used SSRS reports.

So We have lots of existing SSRS reports  but as per new requirement we want to change existing reports orientation from portrait to landscape. so it's converted successfully through properties property and after print we received changed orientation. but during preview we are not seen changed in orientation. So i want to no is there any features or functionality in SSRS to change preview of existing reports without change in reports design more.   

Thanks ,

Kapil Khare