I need to unlink an old Fios account from my current mobile account as Iwant to link it to my new FIOS home account
From what I found on the website, you have to get a Verizon rep to remove the User ID of the old Fios account and unlink it from My Verizon. You can use the live chat in My Verizon, call, or contact Verizon via one of their social media channels. Ask them to remove the One Verizon ID link.