How do I match changed items?

How do I match changed items?

I have issued invoices where the item was xyz and is pointed to sales-general, for example. I have changed the item to point to sales-something else. When I run a profit and loss report the item still is in sales-general.

What I want to do is refresh all postings so my report makes more sense to me.

In other words ...
Sales - General was $250.

I want it to read ...
Sales - General $0
Sales - Something Else $250

How can I easily make this happen?

Thank you.
Rich