standard program

Hi,

I have standard program LJIIEXU02 in function module module J_1IEX_DEFAULT_EXCISE_DUTY i have to change

follwing as like

IF l_update_cond = 'Y'.

CALL FUNCTION 'J_1I4A_DETERMINE_NEW_RATE'

EXPORTING

usage = 'A'

application = 'V'

calc_date = is_exhead-exdat

procedure = 'JINFAC'.

in above code

delete procedure = 'JINFAC"

and insert procedure = ''ZINEXP'.

what i have done is taken access key and went to edit mode and enhancements then switch off assistant mode i have done modifications but modifications are get reflected .

how i will come to my actual postion.

give me the step by step procedure.