If you've set up an account, you can transfer whole calendar data to your another phone.
If you've not set up an account, sign up on the phone you want to transfer data from.
Then, follow steps below
-Install and open an app
-Tap "Log in with Email/Facebook"
-Enter email address and password
If you did not set up an account, you can get back into the calendar via an invitation.
Ask a member to send an invitation.
Join the calendar as a new member.
If you have any questions, please send email using 'contact us form' in the app.