deleting words to rename files

I'm trying to rename a batch of files in such a way that I can keep a last name, delete the first name, then add my initials to the new name so it's clear that I've processed it. Here are a couple of examples:
Joe Smith_479694_assignsubmission_file_Midterm Paper REVISED
Suzie Jones_479701_assignsubmission_file_Paper 2
I'd like to rename the files as Smith Assignment 1 cjk and Jones Assignment1 cjk
As you can maybe guess from the names of the files, they're papers submitted by students who never follow naming conventions so I've had to give up. (The numbers are generated by the course management system where they turn in their papers.)
It sure would be great if I could automate this. Thanks!
--P
Joe Smith_479694_assignsubmission_file_Midterm Paper REVISED
Suzie Jones_479701_assignsubmission_file_Paper 2
I'd like to rename the files as Smith Assignment 1 cjk and Jones Assignment1 cjk
As you can maybe guess from the names of the files, they're papers submitted by students who never follow naming conventions so I've had to give up. (The numbers are generated by the course management system where they turn in their papers.)
It sure would be great if I could automate this. Thanks!
--P