A creditor transfers the rights relating to an outstanding receivable to another person. If, for example, a creditor assigns an outstanding receivable to EOS, EOS has the right to receive the outstanding payment from the customer. The payment to the old creditor does not discharge the customer of their debt if the customer has been notified about the assignment.
A legally effective assignment requires an agreement between the assignor (assigning party) and the assignee (the new creditor). The agreement of the customer is usually not required.