Changes date of a OneNote page depending on information provided in "Sent" email header from Outlook or a table with "Date/Time" header (VBA). Requires a "LocalTimeToUTC()" function provided elsewhere.

CorrectDateOnPage.vba

Sub CorrectDateOnPage()
    Dim appOneNote As New OneNote.Application
    Dim pageXML As New MSXML2.DOMDocument60
    Dim pageContent As String
    Dim clipboard As New MSForms.DataObject
    Dim tNodes As IXMLDOMNodeList
    Dim tNode As IXMLDOMNode
    thisPage = appOneNote.Windows.CurrentWindow.CurrentPageId
    appOneNote.GetPageContent thisPage, pageContent, piAll, xs2013
    pageXML.LoadXML pageContent
    pageXML.SetProperty "SelectionNamespaces", "xmlns:one='http://schemas.microsoft.com/office/onenote/2013/onenote'"
    
    ' Find the date the email was sent, or look for "Date/Time" table row
    Set tNodes = pageXML.DocumentElement.SelectNodes("//one:T")
    For i = 1 To tNodes.Length
        If InStr(1, tNodes.Item(i).Text, ">Sent", vbTextCompare) > 1 Or tNodes.Item(i).Text = "Date/Time" Then
            datesent = tNodes.Item(i + 1).Text
            Exit For
        End If
    Next i
    If tNodes(i).Text = "Date/Time" Then
        theDate = CDate(datesent)
    Else
        theDate = CDate(Right(datesent, Len(datesent) - InStr(1, datesent, " ", vbTextCompare) + 1))
    End If
    isodatestring = Format(LocalTimeToUTC(theDate), "yyyy-mm-ddThh:mm:ss.000Z")
    Debug.Print isodatestring
    Set tNode = pageXML.DocumentElement.SelectSingleNode("//one:Page")
    tNode.Attributes.getNamedItem("dateTime").Text = isodatestring
    appOneNote.UpdatePageContent pageXML.XML, , xs2013
End Sub