Back to one of my favorite topics, and the source of my current headache, 'Windchill Permissions'.
Our preferred change process would be to prevent users from creating New Revisions unless they have been directed to do so by an approved Change Notice (and subsequent Change Task). Unfortunately, I am having trouble making this happen.
If I take away their ability to create new revisions whenever they please (removed the policy rule), then it seems that they also lose the ability to create a new revision during the Change Task Implementation.
To get around this, I'm thinking about adding a new state to the life cycle ('Pending Change'), and using a workflow expression to set this state (and later set it back). This way I could assign 'New Revision' permissions to this state, which would only ever appear during a Change Task Implementation.
The only other solution I can think of would be to assign the needed permissions 'Ad Hoc' during the workflow. But I'm not sure there are methods that would allow me to do this.
If anyone has any suggestions I would appreciate hearing them.
Probably not an option for you but two-phase lifecycle and versioning solves this fairly well. For numbered Revisions and a subset of lifecycle states, all can Revise as desired. For Letter Revisions and other lifecycle states, Revise can only be done by a subset of users, and only on Change Tasks.
Without that, probably the only way is to investigate using permissions that are associated with having an assignment - something that is supposedly possible but have never tried it. If you get that working, please post "how-to" details.