Linking an account to an item allows you to make a connection between the items you sell and how those sales affect your business' bottom line.
You can change the account linked to an item by editing the item. This change can affect all existing and future transactions, or future transactions only (depending on the account field you are changing).
Note: Be sure that there is no Accountant's Copy out for review when trying to change the item; if so, you will not get the option to affect the changes for past transactions.
Changing the Asset or Cost of Good account will not give you the prompt to change prior and future transactions. It changes them all automatically
Changing the Account for a Service Item, Non-Inventory Part, Other charge, and Discount items or changing the Income Account for an Inventory Part will prompt you to allow changes for future only or all transactions.