App that allows to edit reply to invite?

[Ittay Dror]

I'm looking for an app that gives me the option to edit the reply to a meeting invite before sending (e.g., so I can give a reason before declining). The meetings are from exchange, so I need it to support that.
It wolf be great if it has a widget showing a day view (not agenda). If the app doesn't have one, then can you recommend a separate widget that can be customized to open the calendar app?

Thanks!