Its really unclear to me what you are asking. You want the "difference between to [sic] columns", but the only two columns shown are character strings in the left column and numbers in the right column, and you cannot compute a difference between character string and numbers.
Please start by showing us (a portion of) the data that goes into PROC REPORT. Then explain and show us clearly what the desired results are from PROC REPORT.
I've been asked to automate the existing report. I'm having trouble with creating the change line below. I'm hoping somehow I can just use that summarize command to create the change but I do not know how to change the summarize function to be a difference. Any help anyone can provide would be appreciated.
ods _all_ close; ods noresults; /*closes resluts window and directs output to file */