Modify a sapform or sapscript

Hello Gurus, i need to modify an existing sapform or sapscript, i don`t know witch one is it. I am beginner to sapforms and sapscript, i only used smartforms.

I have to modify the output design in program "/CEECV/RO_RFBILA00", and i can`t find this sapform or sapscript. I found a call to a function OPEN_FORM that has the parameter

form = scr_form,

i tryed to open the form with se71 .....

when i double clicked the name "scr_form" it took me to an include that had only parameters, and there is no START_FORM function call; i can`t find anything, please help.