If Else statement only working for the last row of data in Excel VBA Userform

I'm struggling with something that sounds very simple, but there's something wrong with my code.

I have a userform with 2 textboxes when I type a 'serial number' in textbox 1, the 'RMA Number' in textbox 2 auto populates if the serial number matches an existing field in the 'RMA' column in the sheet.

If it does not match I want textbox2 to clear up or say "No Match"

I did the If-Then-Else type of code but it seems to work only for the very last entry at the moment...

What do I need to change in my code so it can match all the entries AND clear up when the Serial Number does not match??

    'Autopopulate RMA# with Serial Number

     Private Sub SN_TextBox1_Change()


     Dim serial1_id As String
     serial1_id = UCase(Trim(SN_TextBox1.Text))
     lastrow = Worksheets("RMA Tracker").Cells(Rows.Count, 1).End(xlUp).Row


       For i = 1 To lastrow
          If UCase(Worksheets("RMA Tracker").Cells(i, 4).Value) = serial1_id Then
          RMA_TextBox1.Text = Worksheets("RMA Tracker").Cells(i, 1).Value
    
    
          Else
    
           RMA_TextBox1.Value = ""
   
    
    
          End If
    

       Next i


      End Sub