How do I say "She's changed a lot" Is there a colloquial way to say "A person has changed a lot"? 
For example, I'd like to say "I know she has changed over the past couple of years because of doing stand-up comedy" 

Would it be 
"我知道他因为开始Stand－up就变了很多” or is it “有很多变化？”
Any time in doubt about how to put some expression into Chinese, check something like jukuu.com

她变了很多 in this case would fit. But 她变化很大 would also be OK.