Hello Nesa1,
Welcome to the community!
As previously mentioned, it is not possible to port a Fido line to another Fido account. You would need to request the Transfer of Responsibility (see also here). You should note that there is a fee to perform the responsibility transfer (see here).
You should also note that the line would not be considered a new activation for Person Y. That is, the line would not be eligible for any new activation promotion plans.
**edit**
@Nesa1 wrote:
The end result:
Person Y Fido Account would have 2 lines (604-111-1111 (existing plan; no changes), 604-222-2222 (new plan))
To clarify, did you wish for Person X to take over Person Y's plan or to keep their old plan during the transfer? If you did, you should note that the plans are associated with the phone number and not necessarily the account. Plans are not transferable between phone numbers. In addition, Person X would not be able to get the same plan as Person Y (unless the plan is currently in-market) or vice versa, even though they would be on the same account.**
Hope this helps 😀
Cheers
Hi Nesa1!
To answer your question, i'll say it's possible to transfer a number or an account to another person or to another account even your engagment and contract but the number and account is linked to your name before the transfert. The way best to do it's in a Fido shop. It's will automatically cancel your contract once the transfert process is completed.
I hope you enjoy my answer! And have a nice day 
Hello @Nesa1,
You won't be able to port a number from one line/account to another.
What you are looking to do is called a transfer of responsibility so you can transfer the other person line to your account and then you can change the plan if required.
If that person only have that one line on the account once the transfer has been completed it will cancel the account.
You can contact customer service and they will be able to assist you with the transfer process.
