Functionality
This function module checks the changeability of purchase order data atheader and item level.
Every purchase order contained in the Changing_Header or Changing_Itemstables is checked to see whether it has been released and whether anyfollow-on documents (order history) exist. If it has already beenreleased or if an order history already exists, you get an Error_Status'W'. An Error_Status at header level is transferred to any items thatexist.
The setting of the delivery completed indicator (EKPO-ELIKZ) is checkedat item level. If an error occurs during the check, the error is shownby the Error_Status 'E'.
If an Error_Status has been set, it is logged in the E_ERROR_MESSAGESerror table.

Notes
IMPORTANT: The internal table,CHANGING_HEADER, must be sorted bydocument number. There must be no multiple entries of document numbersin the table.
The same is true for the CHANGING_ITEMS table. This table, however,must be sorted by document number, document items and schedule lines.Multiple entries are not permitted.
If the optional tables I_EKKO and I_EKPO exist, they must also besorted correctly.

Further information
To check header data (release, order history) the function module callsthe related function module WPOCC_CHECK_CHANGEABLE_PO_HEAD.