modify code to make i is dynamic range in code

the complete code as the following

Sub loop()

  Dim ws As Worksheet
  Set ws = ActiveSheet
  Dim rng As Range

Set rng = Sheets("sht2").Range("A15")


  Dim lastRow As Long
  lastRow = ws.Cells(ws.Rows.Count, 15).End(xlUp).Row
  
  For i = 2 To lastRow

rng = Sheets("sht2").Range("O" & i)
Call action1
Next i
  
End Sub

Are you trying to convince us that the procedure named 'Sub loop()' (small letter "L" in "loop") will run at all ?