Let's say that I have many shared_ptr<A> sharing ownership to the same A object. At some point, I would like all those shared_ptr to point to a  new  Object A. Is there an easy (and safe) way to accomplish that?
I know how to do that for one shared_ptr using either "reset", either operator =  but in order to do this for all shared_ptr sharing ownership, the only way I could think of is through a registration mechanism (like the Observer pattern) but this sounds an overkilling process to me.