@James4425
Unfortunately, you can't cancel the reservation (without penalty). It is the Host's responsibiity to always monitor their pricing, whether using Smart Pricing or a 3rd party Dynamic Software.
Many Hosts don't use Smart Pricing (it's not very smart) for this reason (and others). It is not very good at predicting demand far out like in your case and doesn't always capture local events in the area that would necessitate an increase in price. You can always manually override a smart price on your calendar, but that means you have to actively monitor your pricing and not rely on Smart Pricing (or any 3rd party pricing software) 100%.
Smart Pricing
https://www.airbnb.com/help/article/1168