How to fill out the Cook County Professional Services Agreement Document? 1. Review the entire document thoroughly. 2.The Water Authority shall pay Design Professional for services performed in accordance with this contract before the date of termination. Reference Number: Enter Project Number. Order Number: Enter E1 Order Number. A plain language, highly structured agreement for professional services. Use for single or multi-project engagements with or without deliverables. Explore the essentials of professional services agreements in our mustread guide.