From the page of the event that you want to edit, update the booking dates to show correct. If the bookings are showing as closed incorrectly, you can reset this here by adjusting the closing time, before resetting it to the original time.

Once the times are correct, scroll down to the bottom of the section, and click the update button, then select: Apply to event and all items (classes).

Please note that if you click Apply to Event ONLY, the event banner will show the booking dates as open, however, the individual items (classes) will still show as bookings closed.

You are able to check that the booking dates have been updated correctly by previewing the event. To do this, click on the preview event icon to be able to see what the public would see when searching for your event.