Auto-enter on Modification or on Creation?
If on Creation and it's still a date field and not a calculation field, just enter each field and edit the date.
If it's an On MOdification field option, Go into Manage | Database | fields, pull up field options and turn off this feature. Correct the dates, then return and turn the feature back on.
This kind of "oops" is why you should also make frequent back up copies while doing development work on your file. With a back up copy, you might not have to go back and change the dates one record at a time.
Here's a way to automate that so that you don't forget to keep making back up copies: Saving Sequential Back Ups During Development
thanks. ill be sure to do that.