What is the difference between substituting and waiving a course?
You should petition for a substitution when you have taken a course at another institution or department that is similar to a required course in CDFS. You should petition to waive a course when you have previous experience but no coursework related to a required course in CDFS. See the Graduate Manual for documentation requirements for petitions. All petitions (especially for core courses) should be submitted during the first semester in the graduate program.