Uppercase to lowercase in VS COBOL II

The easiest thing to do would be to start using the newer compiler (I am sure you have it installed somewhere) and use the built in function, LOWER-CASE. (By the way, VS COBOL II went end of service in 2001.) LOWER-CASE is available in all IBM COBOL compilers since 1991. It works like this:

Move Function Lower-Case(INPUT-FIELD) To OUTPUT-FIELD 

In VS COBOL II, you could use INSPECT CONVERTING, something like:

Inspect INPUT-FIELD Replacing All 'A' by 'a' 
                          'B' by 'b' 
                          'C' by 'c' 

and so on.