A prior accountant set up account numbers in our chart of accounts using a 4-digit convention, which I would like to change.  As an example, 64XX is "Office and Administration" and 66XX is "General and Administration".  I want all these expenses to be in the 64XX series.  If I change account numbers of existing accounts, will the legacy transactions be updated with the new account number or will they still show the account number which existed on the date when the entry was posted?  Thanks for your help.