Hello there[url=https://cdn.discordapp.com/attachments/902560216871239752/978300950097842206/giphy.gif],[/url] In order to unlink an account, you first have to disable cross save and/or unlink accounts, you must be able to authenticate the accounts. Bungie cannot forcibly de-link them. [b]I would suggest contacting the platform concerning gaining access to the platform account.[/b] If you are unable to gain access to the account, then you will not be able to deactivate cross save or unlink it from your current Bungie.net profile.
No, there is no other way.