Having worked on the front line for quite a few years as rep and then as duty manager, one of the biggest things that can make or break a situation is communication.
My phone was often like the BT exchange during these types of events and quite often if ops where trying to swap things about, what was told 10mins ago had now changed.
Its a tricky one sometimes but no matter how bad the situation is, as a rep or duty manager, you have to take it. If it's handled correctly from the start with honest information then you can have the plane eating out of your hand, mess it up and they can be your worst enemy.
If you're there, no matter what time of day and no matter how long for and people can see you are trying to help, give information, be supportive, empathetic but also firm and to try an explain the situation, this is what makes the difference.
Had many delays in the past with one pig of a summer once, 3 hotac's one after the other but always, we were there and communication is key. To send 300 ibiza pax into a hotel with a 24hr delay is no easy task but didn't hear a peep out of them. Again, it's all down to the individual / team and doing what you can.