Hola Marco,
yo cambie datos del Interlocutor con la Bapi 'BAPI_SALESORDER_CHANGE'
esta bapi maneja la estructura BAPIPARNRC (Modificaciones Interlocutor),
Yo la mande llamar asi :
CALL FUNCTION 'BAPI_SALESORDER_CHANGE'
EXPORTING
SALESDOCUMENT = SALESDOCUMENT
ORDER_HEADER_IN = ORDER_HEADER_IN
ORDER_HEADER_INX = ORDER_HEADER_INX
TABLES
RETURN = RETURN
ORDER_ITEM_IN = ORDER_ITEM_IN
ORDER_ITEM_INX = ORDER_ITEM_INX
PARTNERCHANGES = PARTNERCHANGES
SCHEDULE_LINES = SCHEDULE_LINES
Suerte!
