If you would be late, you must then immediately stop operation of the business completely.  You are considered not licensed to operate if your license expires.  Any services that you provide through your school license including Instructor Certificates, account to DMV's online road test appointment scheduling system, and authorization to order Pre-Licensing Course Completion Certificates will be terminated.  Until you correct the situation and have your new license issued, your instructors will not be able to teach for your school and your school will be unable to provide lessons to customers, teach the Pre-licensing Course, schedule road tests or bring customers to a road test.
Will I be able to renew my license for my school if it is expired?
You can renew the license up to six months after the previous license expires but any operation of your business between when your driving school license expired and the new license is issued will constitute unlicensed operation of a driving school, which could result in your having to pay a civil penalty of $1,000 and/or denial of future driving school license operations.
What was the document that I needed to renew my license if my school does use vehicles for instruction?