How to delete Mail Piece Job files in Mail360 Data Manager

Mail360 Data Manager all versions
Mail Piece files (also referred to as Job Files, or Mail Piece Job Files) are files containing information about mail pieces being mailed out to recipients (Bills, etc), and/or about Mail Pieces being returned to the business mailer (Payments, Product Orders, etc.)  
The Mail Piece Files should be loaded into Data Manager (DM) prior to any scans being received from the USPS for the pieces, as loading the files in advance is what prepares DM to correctly process USPS scan data when it's received .

Sometimes a Mailer may want to delete a Mail Piece file that was already ingested, for example due to the mailing not being mailed out, or the mailing being changed in some way. 

The DM User's Guide for the version being used has instructions for deleting the job files.

For the current DM version 3.1 (as-of Nov 2016) the instructions are found in the "Working With Jobs" - "Searching for Jobs"  section.  Page numbered 24 says-

6. To delete the job, click the Delete Job link. You will see a confirmation dialog box.
You can delete a job, only if you have the permissions to do so. 
In addition, you cannot delete a job if, (1) there exist an associated Mail.dat® or matching scan events
(Confirm®, ACS™, or 2) Start-the-Clock) in the system.  How to delete such a job, refer the
instructions for the manual job rollback process explained in the MAIL360 Data
Manager™ Operations Guide.
UPDATED:  August 9, 2017