You are an original. There has never been and never will be another human being who will have your perspective, your goals, your connections, your circles, your influence. Ever!
You are not a stand-in replacement for someone else. When God calls us to do something and we feel we are not up for the task, it will not be done with the same blessing from someone else. Ever!
You cannot ever be replaced! If God is laying a special task on your heart, you need to step up and be there!