If a new room is added on the same reservation, you don't need to create a new reservation but you can add this room from the existing booking.
To add a new room on a reservation, go to > Reservations in your Amenitiz administrator area left sidebar.
You will find all your bookings. Click on the booking you wish to modify and on "view booking details" :
On the summary section, click on "Add accommodation". You will have the list of your accommodation and their availabilities for the dates of stay of this reservation:
You can add the accommodation, and you will be able then to select the number of adults, children, the price of the stay and add extras for this accommodation.
Adding a new accommodation will update the total amount in the payments section, but the payments made or upcoming payments through AmenitizPay will not be updated automatically. Find out how to charge a card if you added a new charge, or how to refund a client if you deleted or cancelled a charge.