Plugin for Ordering Process

I’m looking for some advice regarding OpenCart plugins.

I want to be able to place a manual ‘review stage’ into the ordering process. So a customer would submit their order, the retailer would receive a notification and review the order (at this point the order may be changed – items removed, total adjusted etc) then the customer would be sent an email informing them to complete the order and pay.

Does anyone know of a plugin or system that includes this type of functionality. I’ve been looking at using OpenCart but I’m prepared to look at other eCom systems.

Thanks