How to Debug Call transaction ?

Hi ,

I want to debug a BDC program . In the debug I want to change the MODE value to 'A '. Currently it is hard coded . Statement in the code looks like this

CALL TRANSACTION 'VL01N' USING bdcdata

MODE 'N'

UPDATE 'S'

MESSAGES INTO messtab.

I dont have the option to modify or copy the code.

Please let me know is theer a way to do it ? Thank you very much in advance.

Thanks & regards

Nanaiah