Howto transform existing pdf landscape2portrait?

I've a pdf file, i want trasform landscape to portrait, can i recognize this problem?

Hi,
Not sure if it will be helpful for you bit some PDF pages can be rotated and have Rotation attribute in PDF. In this case Adobe Acrobat shows them correctly (it applies rotation when render page as far as I understand). I use following code to Render such pages correctly.

long nDPI = _Module.GetDriverSettings()->GetPDFRenderResolution();
double dWidth = GetPDFLibrary()->DAGetPageWidth(m_nPDFFileRef, m_nPDFPageRef);
double dHeight = GetPDFLibrary()->DAGetPageHeight(m_nPDFFileRef, m_nPDFPageRef);
long nRotation = GetPDFLibrary()->DAPageRotation(m_nPDFFileRef, m_nPDFPageRef);

//change height and width if page is rotated
if(nRotation == 90 || nRotation == 270)
{
            double dTmp = dWidth;
            dWidth = dHeight;
            dHeight = dTmp;
 }
 //transform width and height to inches and after that to pixels
 dWidth = dWidth*nDPI/72;
 dHeight = dHeight*nDPI/72;

Best regards,
Kirill