Best Answer
Howdy! Just a passing travelling forum volunteer stopping by... Hehehe
Actually, this question seems to be more about how the process works, rather than requesting it. I can answer this one easy peasy. 🤣 A customer of E.On Next probably could answer it as well under the same context... If there were actually any customers helping out here, which there currently aren't. Just a heads up, I don't use templates or canned replies, so everything I post is hand-written and personalised based on the individual question. It might also be a little more overengineered than it needs to be, but I'd rather answer the question properly on the first try than have to fix my answer later.
This answer is based on my general knowledge from the supplier I'm actually with, but it's close enough for all of them. If you want to add a second person to your account on the basis of Secondary Contact Financially Liable, this usually has to be done over the phone because verbal consent is needed from both the existing account holder and the person that would like to be added. It cannot usually be done via any other method because there needs to be a call recording with the consent given. Once granted, your contract is modified to include the secondary contact who essentially gets all permissions that you have - and also becomes financially liable for the account in the same way you are (and may require a credit check on their side). If you stop paying the bill and fall into debt while this agreement is in place, you can both be chased for payment, so you should only set this up if you understand and accept the risks.
However, if you'd rather not have quite as much risk, there's also sometimes the Secondary Contact Non Financially Liable option, which lets the second person do most things on the account, but without being financially liable at all and presents the secondary contact with zero liability and zero responsibility for maintaining the account. It's the safer option if you just need someone to speak on your behalf for example, or if you'd rather not make someone else liable for the bills.
I hope this helps. I can't make changes to your account, but I can definitely explain how these processes work if you're still unsure.