vba word: If Then find and replace - vba

Question

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

Answer 1

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