You can get a non-commercial duplicate license online  after the effective date on the downgrade notice.Since then your commercial class license document will no longer be valid.
What is the address to replace a REAL ID by mail?
If you would like to accomplish that by mail, you can send your request and check or money order to NYS Department of Motor Vehicles, 207 Genesee Street, Suite 6, Utica, NY 13501-2874.