You can change your email address for your Roamless account from inside the Roamless mobile app:
Open your Roamless app > Profile tab > Account Settings
Click on "Edit" > Follow the on-screen instructions
If you have signed up with an SSO login, you need to first set a password for the underlying email address for your SSO. Afterwards, you can change your email address as you wish.
You can also 'disconnect' your SSO login method from your Roamless account if you need.