This should be the first thing on your to-do list. If you do not give a heads up to your clients and business connections, you may face a serious setback due to the chaos in the company's management. Do notify your business connections about the relocation, send them the new company address, and notify them about the relocation and the change in working hours. Notify them about the opening date and time and the working hours of the new office and always ask for an apology for the inconvenience caused due to the relocation. After all, you would not want to disappoint them and also would not want to waiver their faith!