The Till Reconciliation shows you all transactions that have occurred on the selected date.
Once the till reconciliation is displayed, there are two further options :-
Update the payment Type
If the payment type has been mis-recorded (eg Credit card instead of cash) then this can be updated by double clicking on a line :-
Close the Till Reconciliation
Once the till reconciliation is reconciled for the day, further updates can be prevented by clicking the "Close Till" button.