change the value of parameter in smartfrom by program lines...!

Hi experts.........!

i want to change the value of parameter 'x1' which i import from program has a value 'ECNC' and want to display in output of smartfrom as 'ECNEC'. how i change it from program lines.

I use program lines to change its value....... use input parameter 'x1' and output paramter 'x1'

and program lines are

IF x1 = 'ECNC'.

x1 = 'ECNEC'.

ENDIF.

and in condition i use

x1 = 'ECNC'

but it doesn't effect output is same as it show the value of x1 = 'ECNC' when i execute the program.

How i change the value of x1 to 'ECNEC'

Plz help me.......!

Thanx in advance....!