'Load the PDF document.
Dim loadedDocument As New PdfLoadedDocument("Input.pdf")
'Create a new PDF document.
Dim document As New PdfDocument(PdfConformanceLevel.Pdf_A1B)
Dim startIndex As Integer = 0
Dim endIndex As Integer = loadedDocument.Pages.Count - 1
'Import all the pages to the new PDF document.
document.ImportPageRange(loadedDocument, startIndex, endIndex)
'Save the document.
document.Save("Output.pdf")
'Close both document instances.
loadedDocument.Close(True)
document.Close(True)