Visit https://user.frontierstore.net/ and log in using the credentials of the Frontier account you’d like to unlink.
On the User Information page, navigate to the bottom-right and click the UNLINK button next to the Steam or Epic Games account you wish to unlink from.
A confirmation message will appear.
If required, you can now link the Frontier account to a different Steam or Epic Games account by selecting the relevant option in the Linked Thirdparty Accounts section of the User Information page.
If you have any issues with this, please contact our Customer Support team via the button below, and they will be happy to help you with this.