Login to your Sygic account https://accounts.sygic.com, then select the "Account settings" option in your account overview and scroll down - you will find the "Change Email" option there.
FAQ (Frequently Asked Questions)
How do I change my email address in the app?
Changing your Sygic account email address is not available directly in the app. You can change your email address only in your Sygic account https://accounts.sygic.com.
What should I do if I no longer have access to my old email address?
You do not need access to your old email address to change it. If you remember your password, simply log in to your Sygic account and update the email address in Account.
I don’t see the “Change Email” option – why?
The option to change your email address is available only for password-based Sygic accounts.
If your Sygic account was created using a social login (Google, Apple, or Facebook) instead of an email address and password, the account is linked to that provider and the email address cannot be changed in the Sygic account settings.