Modify source physical file member in RPG

["Deese, Cynthia" <Cynthia.Deese@xxxxxxx>]

Hi,

I'm sure this is a basic question, but I can't seem to find any
direction/documentation or examples on how to do this.  I need to modify a
source physical file member from within an RPG program.  I will probably be
scanning and replacing data or just overwriting whole lines (records) of
text, but I would be grateful if I could get a little help in how you work
with these files within the context of an RPG program.

Thank you.