You can modify the selected record in the subform in the AfterUpdate
event of the combo box.
Private Sub cboStatus_AfterUpdate()
subForm1.Form!Status = cboStatus
End Sub
This assumes that your combo box control is named cboStatus
, your subform is named subForm1
, and the field you want to update is named Status. It also assumes you aren't using numerical ID's as foreign keys for your values.
You will only be able to update one row at a time.
Beyond the scope of your question....
There are numerous other ways to develop an interface to edit the row. One way is to modify the field Lookup properties in the table. You can change the Display Control to a Combo Box, set the Row Source type to Value List, and then set the Row Source to a list of possible values separated by semicolon.

Now whenever you open that table in a datasheet view (like the example on your subform) a dropdown will appear in that column. A user can edit directly in that view without requiring a separate combo box control.
