If you have already given a student marks for an assignment in Blackboard and you wish to change the marks which you have given, you may do so in the Grade Center.
Access student submissions by entering into the Full Grade Center.
You can learn more about the Full Grade Center here.
Select “Full Grade Center” to view all student submissions and marks against all assessment items in your module.
From here, you can click the grade you have given a student for a particular submission and change the grade by typing in a new number.