METHOD FOR UPDATING A FILE

A method is disclosed for retroactively inserting a transactional change into a file where the file involves a plurality of images that are recorded (i.e., saved) at preset sequential time intervals. Each image contains all pertinent information relating to the file subject matter, such as an insurance policy or the like, existing at the time of its saving. The image which immediately precedes the effective date of the desired retroactive transactional change is retrieved, updated to the effective date, and then subjected to the program sequences of backing out, applying and reapplying. The resulting corrected image overcomes the prior art processing problems of prorating, policy cancellation and foreign record origin for a file.