This is one of the techniques to mass change data in NAV.
- Create a new report, selecting the table you want to fix.
- Set the ProcessingOnly property as shown below
CAUTION: Make sure you set a filter on the dataitem to prevent accidental changes.
// set a hard filter to prevent accidental changes setrange(County,'TX');
*** TAKE A BACK UP OF THE TABLE in case you mess it up. Better still test in in a test environment, then run in your live environment***
Then write some code in the OnAfterGetRecord trigger
if "Payment Terms Code" = 'NET14' then "Payment Terms Code" := 'NET30'; modify;