The following will do that:
Sub Macro1()
Dim vFindText As Variant
Dim vReplaceText As Variant
Dim oRng As Range
Dim i As Integer
    vFindText = Array(ChrW(61616), ChrW(61617))
    vReplaceText = Array(Chr(176), Chr(177))
    For i = 0 To UBound(vFindText)
        Set oRng = ActiveDocument.Range
        With oRng.Find
            .Text = vFindText(i)
            .Font.Name = "Symbol"
            Do While .Execute
                oRng.Text = vReplaceText(i)
                oRng.Style = "Normal"
                oRng.Collapse 0
            Loop
        End With
    Next i
End Sub

Sub Macro2()
Dim vFindText As Variant
Dim vReplaceText As Variant
Dim oRng As Range
Dim i As Integer
    vFindText = Array(Chr(176), Chr(177))
    vReplaceText = Array(ChrW(61616), ChrW(61617))
    For i = 0 To UBound(vFindText)
        Set oRng = ActiveDocument.Range
        With oRng.Find
            .Text = vFindText(i)
            .Font.Name = "Symbol"
            Do While .Execute
                oRng.Text = vReplaceText(i)
                oRng.Style = "Normal"
                oRng.Collapse 0
            Loop
        End With
    Next i
End Sub
You can add any other symbols and their corresponding values into the arrays as required.