If you click refuse, it will just tell you to call the reservations centre. After clicking refuse, you can go back and accept them if you want.

I had some minor changes to some of my s/h flights (about 90 minutes, so a little more than yours). I phoned up and explained that the flight arrived too late for the meeting I needed to attend, so they said they would refund me the money. I then bought another flight on Vueling instead.