Worth separating two things people mix up. Your Kitset login is how you get into the editor. Your business email, the one on your contact page, is run by whoever provides your email and has nothing to do with us. Changing one does not change the other.
Step by step
Open Settings in your dashboard.
Change your name or email there.
For a password reset, use the forgotten password link on the sign-in page.
If it does not go to plan
I cannot get in and the reset email has not arrived.
Check spam, then check you are using the address you signed up with. If neither works, email us from any address and we will sort it out.