You can either use the command line qv.exe or an include file (i.e.: a plain text file named "variables.qvs") as follows:
SET pdeptno = 23;
Then in the script you call it as:
$(include=variables.qvs);
When you reload, it will read the pdeptno variable in the variables.qvs file. You can change the value in the QVS file (which is a plain text file, that can be open in notepad) without open the QVW file.