At the moment the date on an invoice is taken from the current date. So, when an invoice is re-issued it takes today’s date. The default date inserted should be the date the invoice was first issued. However, in certain circumstances it needs to be overwritten with a date inserted buy the user. I think this is how it should work.
Invoice date: taken from when the invoice was first issued.
Here is how I think the override would work. I think it will have to be a part of this system where the invoice notes go. So, perhaps a section in there that allows the user to change the date on the invoice to whatever they want.