What I did: I really like Agenda and I have one for my personal and one for work. Currently have an Icloud for my work phone as well so Personal phone. I would like to log into my work Icloud on my personal phone to advance my productivity even more. But it will only sync if it is under the same Icloud. Is their an option that I am not seeing?
Apple does not allow signing in to two iCloud accounts on one device.
If you are not able to sign in to the same iCloud account, you would have to use the Dropbox sync option. You can setup a free account, and use that to sync without having the same iCloud.
Hope that helps!