The only way to edit or remove third-party apps that are linked to your Google account is through the "Manage your Google Account" page on Google.

1. Log into Google
Login to your Google account, then click on your profile picture located at the top right corner of the screen and select "Manage your Google Account".

2. Security > Morningmate
​Navigate to the Security section on the left-hand side menu bar and select Morningmate from the list of third-party apps without account access.

3. Remove access

4. Connect with a new account
​After you have removed access for the previous account, you can link a new account.