If your employer has AMEX platinum or centurion and adds you to his/her account then you can use this wonderful resource. The concierge can hold reservations at multiple restaurants and can sometimes even snag reservations when other resources cannot.
This meal delivery app is great for individualized in-office meetings and events. It uses an intelligent learning platform to get to know individual's preferences and make better and better suggestions.
Discover great restaurants in your city, book reservations and pay the check — all in one app. I have found that sometimes they are able to snag reservations at restaurants other sites (such as OpenTable) cannot.