Manage iOS devices/delete an old iPhone

My FlightAware account thinks I have three iOS devices instead of two. I’m sure it’s my old iPhone. How can I remove this old iPhone?

Your oldest iPone has been removed from your account. Thank you for contacting FlightAware.

So the answer is FlightAware has to remove old devices?

Thanks for the prompt reply.

Correct, we will remove the devices upon request.

I have the same issue. All our three family phones seem to be attached to my account leading to duplicate notifications. Can these be edited please?