Can't update email Address

My ReadyCloud is associated with an old email account that I can no longer access. I can login with no problem using the old email address but will not allow me to change to the email address associated with my Netgear login. Is there a process to merge the old email and the device into the new and current email associated with my Netgear login? It is interesting that the Netgear login shows this and my other devices. Note that I've previously upgraded the ReadyCloud into Netgear several years ago before I moved and lost that email HELP please.

Dan C