Finding only distinct rows

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This is one way to accomplish the task :

Option Explicit


Sub DeleteRows()
Dim Rng As Range

Application.ScreenUpdating = False

Set Rng = Range("A1", Range("C1").End(xlDown))
Rng.Copy Range("M1")

    With ActiveSheet
        Set Rng = Range("A1", Range("C1").End(xlDown))
        Rng.RemoveDuplicates Columns:=Array(1, 1), Header:=xlYes
        
        Set Rng = Range("A1", Range("C1").End(xlDown))
        Rng.Copy Sheets("Sheet1").Range("A1")
       Range("M1:O20").Clear
    End With
    
Application.ScreenUpdating = True

End Sub