Hi,
Did you try using the field symbol after assigning it to data?
FIELD-SYMBOLS <fs_data> TYPE data.
DATA lr_data TYPE REF TO data.
CREATE data lr_data TYPE <type>.
ASSIGN lr_data->* TO <fs_data>.
CALL METHOD me->get_entity_data
EXPORTING
io_access = io_access
CHANGING
cs_data = <fs_data>.