Changing a Reservation 
Use
You can change a manual reservation at any time, even if the reserved quantity has already been withdrawn.
You cannot process automatic reservations.
This section begins by describing the general procedure for changing a reservation. It then goes on to explain several change functions.
How Can I Change a Reservation?
Choose Reservation
®
Change.
On the initial screen, enter the reservation number. If you do not know the reservation number, you can search for it using the Possible entries button.
The collective processing screen for the reservation appears.
You can change the data (for example, quantity or storage location) directly on the collective processing screen. Alternatively, you can select one particular item and change the data on the detail screen.
Post the changes.
Which Data Can I Change?
change general item data (for example, storage location, batch, recipient)
change the requirement date for one item or for all items
change the quantity of a reservation item if you need more or less than the quantity reserved until now
set or reset various indicators (final issue indicator, Movement allowed indicator)
check the availability of the material for the base date specified
delete items
enter new items
Constraints
You cannot change the account assignment data (for example, cost center or order). If the account assignment is incorrect, you must delete the reservation and enter a new reservation.
You cannot change the material number or the plant for an item. If either of these entries is incorrect, you must delete the item and enter a new item.
Availability Check
If you change data relevant to materials planning (for example, quantity, storage location, requirement date), the system automatically performs a new availability check, if this has been defined for the material or for the movement type.
If you do not change any data relevant to materials planning, you can still initiate the availability check manually.