On the system menu, there is a change transaction date button.

By default the date used is today's date.

If the use custom date is selected, you can then select a date you want to use.

This date is used on the 'entered_dt' and 'ord_dt' of the oeordhdr_sql table.

This date only stays in use for the session. If the Point of sale is closed, it resets back to today's date.