Correcting Item Code on Posted Sales Invoice

We have a lot of item codes that are similar, there is a better / faster way to adjust the item code that was used on a Posted Sales invoice besides correcting the entire invoice?

I realize all the COGS implications involved, but is there an alternate way to "switch" the item code used

Example

Customer A was billed item codes on invoice dated 7/15/2018

45 Item A's

55 Item B's

60 Item D's

I would like to switch the 60 Item D's to 60 Item C's.

Or is there a way to move inventory form Item C into Item D ? Just use the Item Journal?