What are the steps for closing a blanket order which is past its cancel date?

We are looking at using the blanket sales order functionality. We've been prototyping and it seems to work pretty well. The blanket order is automatically closed when the entire quantity has been released. We've tried a cancel date and it will not release anything on the blanket past the cancel date. What we haven't figured out is what is the proper process to get the blanket to close once past the cancel date. Is there a program for doing this which we haven't found? Or is there some other manual process people use to find the open/canceled blankets and then