Ability to change Invoice Billing and Shipping Address.

This is really needed. We have a company with multiple branches - they request the billing and shipping to be updated after every invoice, which we cant do until we edit the customer details. This doesn't work as we might have 3 different orders for them, requiring 3 different billing and shipping addresses. 

I understand they can change the details upon checkout - this never happens. They usually get notified by their payment department of the changes needed and then communicate to us.