Is there a way to change the machine number(resource) after a discrete job has been released.

I have defined the routing with say machine number A for an item 1.

When i define a discrete job the above routing pulls in the machine number and the standard operation.

Now if the job is released and the machine breaks down and i want to use machine B instead of A. With job just half done. Is there a way to change the machine number on the job since i am using the usage field to capture effiency rate and would like to see that for a particular job of 100 items 25 were produced on Machine A and the rest 75 were produced on machine B.