My kids have a tutor on a Tuesday, I completely messed up and forgot that they are at a school event tonight. I rang the tutor, who is lovely, reliable and great with the kids as soon as I remembered this afternoon. She's going to ring me back and see if we can reschedule for later in the week. If we can't should I offer to pay for the missed session? We don't have a written contract so I'm looking to see what the consensus is on what to do.