Here you go: 

Exciting News! Our favorite charity is on a mission to make a difference in the world and they need YOUR help! 
Join us today and contribute to their cause by donating, volunteering or simply spreading the word. Together we can change lives!

That's wonderful news! Count me in to support the cause and make a positive impact together. Let's change lives and make a difference!

I'm glad to hear that you're joining the cause! Together we can truly make a difference and change lives for the better. Your support is invaluable in creating a positive impact.