vba word: If Then find and replace

in this code, I want to do the following:

• If the word is finished with a letter M Replace with letter N.
• If the word ends with a letter N, Replace with letter M.

• I do not know well using the IF - Then statement. Any help would be greatly appreciated.

  Sub find_end()   
      Selection.Find.ClearFormatting
      Selection.Find.Replacement.ClearFormatting
      With Selection.Find
          .Text = "[nm]>"
          .Replacement.Text = ""
          .Forward = True
          .Wrap = wdFindContinue
          .MatchWildcards = True
          Selection.Find.Execute
          With Selection
          If Selection.Find.Found = n Then
              Selection.TypeText Text:=m
          ElseIf Selection.Find.Found = m Then
              Selection.TypeText Text:=n
          End If
  End Sub
  

I modified the code found at: Repeating Microsoft Word VBA until no search results found and it will spin thru a document and replace the last letter (if it's an 'm' or 'n') of each word. NOTE there is a 'loop check in that code that you may want to remove if it's possible you may find over 2000 m or n's.

Option Explicit

' The following code adapted from: https://stackoverflow.com/questions/13465709/repeating-microsoft-word-vba-until-no-search-results-found
Sub SearchFN()
    Dim iCount  As Integer
    Dim lStart  As Long
    'Always start at the top of the document
    Selection.HomeKey Unit:=wdStory

    'find a footnote to kick it off
    With Selection.Find
        .ClearFormatting
        .Text = "[nm]>"
        .Replacement.Text = ""
        .Forward = True
        .Wrap = wdFindContinue
        .Format = False
        .MatchCase = False
        .MatchWholeWord = False
        .MatchKashida = False
        .MatchDiacritics = False
        .MatchAlefHamza = False
        .MatchControl = False
        .MatchByte = False
        .MatchAllWordForms = False
        .MatchSoundsLike = False
        .MatchFuzzy = False
        .MatchWildcards = True
        .Execute
    End With

    'Jump back to the start of the document.
    Selection.HomeKey Unit:=wdStory

    'If we find one then we can set off a loop to keep checking
    'I always put a counter in to avoid endless loops for one reason or another
    Do While Selection.Find.Found = True And iCount < 2000
        iCount = iCount + 1

        Selection.Find.Execute

        'On the last loop you'll not find a result so check here
        If Selection.Find.Found Then
            ' Exit if we start back at the beginning
            If Selection.Start < lStart Then
                Exit Do
            End If

            'Reset the find parameters
            With Selection.Find
                .ClearFormatting
                .Text = "[nm]>"
                If Selection.Text = "m" Then
                    Debug.Print "found 'm' at position: " & Selection.Start
                    Selection.Text = "n"
                ElseIf Selection.Text = "n" Then
                    Debug.Print "found 'n' at position: " & Selection.Start
                    Selection.Text = "m"
                End If
                lStart = Selection.Start
'                .Replacement.Text = ""
                .Forward = True
                .Wrap = wdFindContinue
                .Format = False
                .MatchCase = False
                .MatchWholeWord = False
                .MatchKashida = False
                .MatchDiacritics = False
                .MatchAlefHamza = False
                .MatchControl = False
                .MatchByte = False
                .MatchAllWordForms = False
                .MatchSoundsLike = False
                .MatchFuzzy = False
                .MatchWildcards = True
            End With
        End If
    Loop
End Sub