I there I am trying to find out if I can change all my customers terms from Net 30 to net 15 at one time.

Export the list of customers with Net 30 Terms to Excel with a Filter and only the Customer number, Customer Name and Terms Code in the Grid.

Import the list using a Template for Customer Number, Filler, Filler, and default the Terms code to "Net 15".

Make a backup before performing this routine.