You have 30 days after the expiration date to renew and take the course. If you miss this time frame, you will have to apply for a new commission.
Submit renewal application online with the Maryland Secretary of State website
https://www.egov.maryland.gov/sos/notary/#/home
Once approved - you have 30 days to pick up commission and take the notarial oath of office.
*The Secretary of State does all communication electronically now, so make sure they have your correct email address. *