Hello - I am on week 27 in my plan. I just finished my A race, in Des Moines this past weekend. I had a B race on the calendar for 9/12, but ended up qualifying for Ironman 70.3 Worlds, which is a week later.
How can I make this an A race, push the race date to 9/18, and have my plan updated accordingly?
Thanks!
First up, congrats on qualifying for Worlds. 
If your existing plans extends beyond 9/18, just add the Worlds as a new A event on your calendar. You will be prompted to allow the plan to be recalculated. Once this is done, delete the B event.
If your current plan does not extend beyond recovery from your just completed event, then create a new plan with the new A event, but backdate the start date to pick up your previous Base/Build