A party may direct written interrogatories to any other party. A copy of the interrogatories shall be served on all other parties entitled to notice.Chicago, Illinois, at or before pm on. 1. The full name and complete last known address of every witness to the occurrence complained of. Interrogatories are written questions that one party sends to the other. The receiving party is required to answer these questions under oath. Certificate of service of discovery document. Service of discovery shall be made in the manner provided for service of documents in Rule 11. If you fill out a form on a webpage, you will lose your progress. Please be aware that forms will be displayed in a NEW browser window.