Elen,
I’ve resolved the issue and the cancel button is now available for this trip.
For future reference, for any trip leader that changes the date of their trip, they also need to update the “Cancel Before Date” date. The problem was that the “Cancel Before Date” was set for the original date of the trip which meant that the cancel date had already passed. I have updated the “Cancel Before Date” to 7/31 so now the “Cancel” button is available.
…MIke