Convert a Change Order to an Opportunity

Here is an example we are dealing with :

We have a completed project with a good customer of ours, by completed, the work is complete, the payment is complete. The only thing is pending change order that is not yet accepted. Since we deal with the client's representative in that particular case, we are asked to keep this Change order active , on "the backburner" and it should be accepted and the work carried in the upcoming months.

We ask our project managers to complete their projects but they can't "finish" them knowing that a change order is still "alive". If they were to complete the project, the sales person associated with that pending change order loses the ability to track and follow-up with that opportunity.