First of all, please bear in mind that you will not be able to operate in your account without enabling the 2FA.
Hence, you have to disable the 2FA if you would like to change the device used for your Google Authenticator account. For that, please press the small downward arrow next to the company name in the top right corner and press Settings. In the newly opened menu please go to Security, press Disable 2FA, enter your password, enter 2FA code, tick the box after reading the text next to it. Finally, press Disable.
During your next login, you will be asked to enable 2FA. Simply follow the instructions on the screen using your new device.