How to "lock" a quote when the status of the quote is "accepted" ?

Hello,

Does anyone of you as an idea about the best way to LOCK a record (in my scenario, a complicated one : a quote) when the status of the record is set to a specific value ?

What we are looking to achieve : when thet quote status is accepted, the sales users are not supposed anymore to change the quote neither the products ; they can only add activities (tasks, calls etc.) and, if a change is required, only the sales manager can do it.

Any suggestion is welcome.

Fred