Ability to Lock a deal

We occasionally have demo vehicles or "showroom builds" that already have a number off accessories and protections onto them. In order for the sales staff to know what is already equipped to this vehicle we will often build an AutoVance deal for them. However, it is typical for a sales person, when working a deal on that vehicle, to either add things and sometimes even remove (if the client decides to go with the same model but not the demo). It would be fantastic if there was an ability to have management have the ability to lock a deal so it cannot be changed.