VSCode 1.106.2, November 2025 version.
Option 1 (through the extensions list):
In the extensions view, right-click the GitHub Copilot extension or click the "manage" gear icon on it.
In the pop-up menu, select "Account Preferences".
Option 2 (through the "Command Palette"):
On press F1 or Shift+Ctrl(Cmd)+P to get to the VSCode Command Palette.
Type: "accounts manage" and select the "Accounts: Manage Extension Account Preferences".
A list will show up, showing all extensions that support account logins. Select the "GitHub Copilot Chat".
On the top (command palette) it will show your account name, the second option will be "Use a new account...", which takes you to the web login.