Using of field symbol

Hi guru, i have a problem.

I have to call a method which uses a parameter type data.

    FIELD-SYMBOLS <fs_data> TYPE data.

    CALL METHOD me->get_entity_data

      EXPORTING

        io_access = io_access

      CHANGING

        cs_data   = <fs_data>.  <---This parameter is defined type data

I tryed to use field symbol type data but it dumps because the field simbol is not assigned.

If i use instead a type ref to data the method dumps because the field symbol has a different type.

    DATA lr_data TYPE REF TO data.

    CREATE data lr_data TYPE REF TO data.

    ASSIGN lr_data->* TO <fs_data>.

How to solve it?

thank you