Launch the Blitz App or access the web version of Blitz.
Click the cogwheel icon located at the bottom left of the sidebar to open the Settings menu.
Within the "All Games" section, locate your current email address and click the "Edit" button next to it.
Type in the new email address you want to use, and click "Confirm."
Check both the old and new email accounts for verification emails, and follow the instructions to confirm the change.