Option Explicit

 '*** ActiveX Control Event *** 
Private Sub Command1_Click()
Dim str1 As String
    str1$ = "П" & Chr$( 97 ) & "па + Мам" & Chr$( 97 )
    If InStr( 1 , str1$, Chr$( 97 )) Then
        str1$ = ReplSymbol(ByVal str1$, ByVal Chr$( 97 ), ByVal Chr$( 224 ))
    End If
    Debug.Print str1$
End Sub

 '/* >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
 '/* Заменяет в строке один символ на другой 
Private Function ReplSymbol(ByVal strConvert As String, ByVal strSymb1 As String, ByVal strSymb2 As String) As String
Dim i As Integer
    i =  1 
    Do While i <>  0 
        i = InStr(i, strConvert$, strSymb1$, vbTextCompare)
        If i <>  0  Then Mid$(strConvert$, i,  1 ) = strSymb2$
    Loop
    ReplSymbol$ = strConvert$
End Function