I did inquire about this issue in a separate topic in the AC forum, but now I realized it's a broader question that relates to Star Alliance in general. (please delete the question in AP forum if you see fit; I'm actually more interested in a general miles pushing, in case anyone ever needs to switch programs WITHIN a year)

So, to keep the question short and to the larger point:

If one realizes that another program within the *A would serve him better, is it possible to cancel all the credits from the last six months and move them to another program with no penalties (i.e. M&M to AeroPlan in my case)? If so, what kind of penalties one is looking into? Is it worth it, if one can get *G with mileage on the "new" program, but would stay *S with mileage on the "old" program?