If you just read the documentation, you will have the answer -> http://help.sap.com/abapdocu_702/en/?url=ABAPCALL_FUNCTION_DYNAMIC.htm
Sorry, I understand your point. But it has been discussed many times in the forum :
FIELD-SYMBOLS <itab> TYPE standard table.
FIELD-SYMBOLS <line> TYPE any.
FIELD-SYMBOLS <field> TYPE any.
ASSIGN ref->* TO <ITAB>.
LOOP AT <itab> ASSIGNING <line>.
ASSIGN COMPONENT 1 OF STRUCTURE <line> TO <field>. " assuming line is a structure
ENDLOOP.
+ see the answer of Tomas Buryanek about the required CREATE DATA before doing the CALL FUNCTION