Verify that you have the correct school name. Phoenix University doesn't exist, but University of Phoenix does. If you have a copy of the degree, look at the name of the institution first before beginning your search. Search for the school online.
Get the full name, birth date and graduation date of the person you want to verify. Ask for the maiden name or other names the person may have registered under. Ask for the degree awarded. When possible, get a signed release of information if you haven't done so on the employment application.
Contact the Office of the Registrar at the school. The registrar will have the date of graduation on file. If you don't want to contact the university directly, you can research the information through a paid service online, such as the National Student Clearinghouse or fax the information to the school. Provide the name, birth date and date of graduation, along with current address. If you have a Social Security number or student identification number, give that information to the registrar's office.
Ask the person for a copy of the degree, certified transcripts and accreditation of the university. A legitimate degree-holder will have these credentials or will be able to get these credentials in a short amount of time.