VBA to Search and Replace??

Ive created a in/out time time clock using "Userform"
it works very well, but it's populating my spread sheet row by row. One employee may punch in at 8am and another at 2pm.
I need a code so when the 8am employee punches "OUT", the Out punch data populates in the original row (instead of creating a NEW row)

here is the code i have so far

Private Sub CommandButton1_Click() 
Dim iRow As Long 
Dim ws As Worksheet 
Set ws = Worksheets("sheet1") 

'find first empty row in database 
iRow = ws.Cells(Rows.Count, 1) _ 
  .End(xlUp).Offset(1, 0).Row 

'check for a part number 
If Trim(Me.TextBox1.Value) = "" Then 
  Me.TextBox1.SetFocus 
  MsgBox "Please enter Required Information" 
  Exit Sub 
End If 
If Trim(Me.TextBox2.Value) = "" Then 
  Me.TextBox2.SetFocus 
  MsgBox "Please enter Required Information" 
  Exit Sub 
End If 

'copy the data to the database 
ws.Cells(iRow, 1).Value = Me.TextBox1.Value 
ws.Cells(iRow, 2).Value = Me.TextBox2.Value 

ws.Cells(iRow, 3).Value = Date 
ws.Cells(iRow, 4).Value = Time() 

'clear the data 
Me.TextBox1.Value = "" 
Me.TextBox2.Value = "" 





End Sub 

Private Sub CommandButton2_Click() 
Dim iRow As Long 
Dim ws As Worksheet 
Set ws = Worksheets("sheet1") 



'find first empty row in database 
iRow = ws.Cells(Rows.Count, 1) _ 
  .End(xlUp).Offset(0).Row 


If Trim(Me.TextBox1.Value) = "" Then 
  Me.TextBox1.SetFocus 
  MsgBox "Please enter Required Information" 
  Exit Sub 
End If 
If Trim(Me.TextBox2.Value) = "" Then 
  Me.TextBox2.SetFocus 
  MsgBox "Please enter Required Information" 
  Exit Sub 
End If 

'clear the data 
Me.TextBox1.Value = "" 
Me.TextBox2.Value = "" 


ws.Cells(iRow, 5).Value = Time() 
End Sub