I call sortable.stop() to make an ajax call to store some data after drag&drop operation.

When the ajax call returns an error (application logic error or net problem) I want to move the dragged element to its original/start position, how can I achieve it?

The scenario should be

1. user drags A to B
2. the sortable.stop() event is called, it triggers an ajax call
3. the ajax call returns an error
4. inside the stop() event we get the ajax error
5. move A to its original position
6. user again move A to B
7. everything is ok
8. A remains in its new position in B

Steps 6-8 are shown to clarify a successive drag can be done and previous error must be forgotten