Maybe you could put a precondition that would check to see if the "Last Update Date" is within the past minute and if it is have an auto action that sends an email to the current assignment.user.
You'd probably have to build it out as a calculation.
Jamie, thank you for your reply. Where would I place the precondition? Is it after the Open status? Would you be able to point me to the right direction of how to code the calculation?
You would almost need it every place where you may want to capture that happening.
Here is a reference to using datetime spans in calcs.
An easier method though may be to set the from read only after a certain point and if any updates need to be made, force them to add a note. Then, anytime a note is added by another other than the owner, notify the owner.