Exactly the same situation I am facing, AZ-AZ, BHP, End of October 2nd shot. On the appointment slip AZ is already noted.
But of course I would like a Pfizer shot - especially because I have suffered quite some strong side effects after the first AZ shot. Maybe the 2nd AZ will floor me then. Anybody tried to change the second vaccine since the policy seem to have been changed anyway ?
I guess it is not possible to change just on the day they will want to administer the shot. Too complicated for them.