Definitions of special endorsement
an endorsement (=signature on a cheque, bill of exchange or other negotiable instrument to make it payable to another person or cashable by any person) authorizing payment to someone other than the person to whom the cheque etc was first given. A check is signed with a special endorsement when you want to give your check to another person.
A blank endorsement is changed into a special endorsement if certain words are written above the endorsee's signature, such as "pay to the order of Y."
some kind of warrant, guarantee, or authorization given by one party about another
A regular driving licence for a light motor vehicle can drive commercial vehicles in the same category without seeking a special endorsement.