Upgrading Enchant MK to Explorer MK

[lalasmama]

I currently have the Enchant MK, and know that I'll need to upgrade to the Explorer MK when it's time to renew, but can I do it before I'm in the 30 renewal window? Essentially, my renewal time isn't until Sept., but Hubs and I are taking a trip in July, and the Explorer MK would cover a few of the days we will be there, so I'd like to upgrade soon so I can make those reservations when the res window opens. If I can upgrade soon, how do I do so? Do I just need to call the Disney MK line? Trying to not call yet because waiting on hold forever drives me bananas!