It's technically not, as long as something hasn't gone wrong or something was of its time and so there is an aspect that is basically tired but can't fundamentally be changed because that is key to what it is. But I don't know whether technically also revitalising and rebranding are the same thing and both would be parts of it having a 'renewal' vs 'do something new'.
It is hard however from a point of view of old habits and logistics and having to communicate hearts and minds (asking people to stop using the old banner or leaflet they had stuck in the cupboard already etc). But the real challenge is getting the ear, interest, information to the end people it is being done for in the first place. And without communicating on or thinking about that 'old' anyway then you still end up having to have the same discussions because the old thing is still there even if what you 'own' is the new thing.
So it just is different issues in different places and parts of the process. The hard bit is getting things coherent or clearly defined/delineated (so people know the difference between one and the other, rather than that question 'why are there two of you' being what dominates responses more than you'd like - whichever way is chosen.
If we are talking about something new from a different place then having its own brand goes with it having its own origins and angle that makes it 'different' to that for example that might be different. Because then it is taking something and then saying 'it's completely different people behind it' that are looking to shape it into the thing they might just have done separately as it is so different in approach.
I think it is an interesting question for discussion if there is a more 'today' alternative that fits better with where things might go eg if research makes headway.