Welcome to planDisney, Brett!
I'm so excited that you have a trip to the Disneyland Resort coming up in just a few days! I am also thrilled that you are considering purchasing one of the new
Magic Key passes. With your multi-day tickets, you have a few options when upgrading to a Magic Key. You can choose to upgrade your tickets on August 25th when Magic Keys go on sale. If you do this, you will need to be aware of any blockout dates that could preclude you from visiting the parks and you will have to make new theme park reservations using a calendar just for Magic Key holders.
The other option is to use your multi-day tickets and
theme park reservations for your upcoming trip just as you would normally. Then, on the last day your tickets are valid (usually the last day you visit the parks, before the parks close for the day), upgrade your tickets to a Magic Key. This way, you won't have to worry about any blockout dates or making new theme park reservations. The only thing you'll need to be aware of is that once you upgrade to a Magic Key, your activation/anniversary date will be retroactive to the first day that you used your multi-day tickets. So, in your case, if you upgrade on August 28th, your activation date will really be August 25th.
You should see the option to upgrade your tickets to a Magic Key in the
Disneyland app after August 25th. You can also stop by a ticket booth to upgrade if you wish. Please keep in mind that the difference between the cost you paid for your multi-day tickets and the Magic Key you upgrade to will be due in-full at the time of upgrade.
I hope this information was helpful! Have a wonderful time at the Happiest Place on Earth!
-Linda