SubDocument BeginUpdateHeader(
    HeaderFooterType type
)

Function BeginUpdateHeader(
    type As HeaderFooterType
) As SubDocument

using (RichEditDocumentServer wordProcessor = new RichEditDocumentServer())
Document document = wordProcessor.Document;
    Section firstSection = document.Sections[0];

    // Check whether the document already has a header (the same header for all pages).
    if (!firstSection.HasHeader(HeaderFooterType.Primary))
    {
        //If not, create an empty header.
        SubDocument headerDocument = firstSection.BeginUpdateHeader();
        headerDocument.Paragraphs.Append();
        firstSection.EndUpdateHeader(headerDocument);
    }
}

Using wordProcessor As New RichEditDocumentServer()
Dim document As Document = wordProcessor.Document
    Dim firstSection As Section = document.Sections(0)

    ' Check whether the document already has a header (the same header for all pages).
    If Not firstSection.HasHeader(HeaderFooterType.Primary) Then
        'If not, create an empty header.
        Dim headerDocument As SubDocument = firstSection.BeginUpdateHeader()
        headerDocument.Paragraphs.Append()
        firstSection.EndUpdateHeader(headerDocument)
    End If
End Using

SubDocument source = sourceSection.BeginUpdateHeader(headerFooterType);
SubDocument target = targetSection.BeginUpdateHeader(headerFooterType);

//Reject all revisions in the firts page's header:
SubDocument header = documentProcessor.Document.Sections[0].BeginUpdateHeader(HeaderFooterType.First);
documentRevisions.RejectAll(header);

//Reject all revisions in the firts page's header:
SubDocument header = richEditControl1.Document.Sections[0].BeginUpdateHeader(HeaderFooterType.First);
documentRevisions.RejectAll(header);

// Modify the header of the HeaderFooterType.First type.
SubDocument myHeader = firstSection.BeginUpdateHeader(HeaderFooterType.First);
DocumentRange range = myHeader.InsertText(myHeader.CreatePosition(0), " PAGE NUMBER ");

{
    SubDocument header = section.BeginUpdateHeader(headerFooterType);
    subDocumentProcessor(header);

If Not sourceSection.HasHeader(headerFooterType) Then Return
Dim source As SubDocument = sourceSection.BeginUpdateHeader(headerFooterType)
Dim target As SubDocument = targetSection.BeginUpdateHeader(headerFooterType)

'Reject all revisions in the firts page's header:
Dim header As SubDocument = documentProcessor.Document.Sections(0).BeginUpdateHeader(HeaderFooterType.First)
documentRevisions.RejectAll(header)

'Reject all revisions in the firts page's header:
Dim header As SubDocument = richEditControl1.Document.Sections(0).BeginUpdateHeader(HeaderFooterType.First)
documentRevisions.RejectAll(header)

' Modify the header of the HeaderFooterType.First type.
Dim myHeader As DevExpress.XtraRichEdit.API.Native.SubDocument = firstSection.BeginUpdateHeader(DevExpress.XtraRichEdit.API.Native.HeaderFooterType.First)
Dim range As DevExpress.XtraRichEdit.API.Native.DocumentRange = myHeader.InsertText(myHeader.CreatePosition(0), " PAGE NUMBER ")

If section.HasHeader(headerFooterType) Then
    Dim header As SubDocument = section.BeginUpdateHeader(headerFooterType)
    subDocumentProcessor(header)