According to the Kellogg website, if you requested an on campus interview then you should call them to schedule it. Here is what they have posted, hope it helps!
Candidates who indicated a preference for an on–campus interview should schedule their interview after submitting a completed application. The schedule will be filled on a first-come, first-served basis, so we encourage candidates to schedule as soon as possible to increase the likelihood of securing a desired date. All interviews must be scheduled and then completed by the listed deadlines. Interviews not scheduled and completed by the appropriate deadlines will be waived.
Please call the Office of Admissions to schedule your on-campus interview. On-campus interviews are conducted by a member of the admissions staff or student admissions interviewers. Interviews are conducted Monday, Tuesday, Thursday and Friday from September through April and on select Saturdays from late fall until early spring. On-campus interviews typically last 30-45 minutes.