Hello Deb-hefferon
Yes you can transfer a client who already has an account to your accountant billing. If you are already added in their manage users as an accountant you would just need to go to the cog in the top right>your account>click on add existing clients>put a tick in the client you want to add>select add clients>continue
You will then see that client under your account> your subscriptions
Any questions let us know
Emma