There is no method to migrate iCloud content from one account to another. You'll have to copy/send/transfer the content of those app manually; each according to the abilities of that app. If nothing below works, then emailing them to yourself is almost always an option, if not a great one.
For the iWorks apps you might be able to use the new Share option to share the documents with your other account. Once you see them there, make sure you have copies local to that account; because who knows what will happen to the other account once you stop using it.
You can go to icloud.com on your laptop and copy your iWorks files to the laptop and into it's iWorks directories.
If you've activated iCloud Drive, then apps that are update for it can copy files directly to DropBox, Box, and some of the other cloud services. You can copy your files there, then copy them back after you change iCloud accounts; if it doesn't seem like a better idea to just leave them on the cloud service.
iCloud Drive is working nicely for me, but if you've got a Mac you'll want to upgrade to Yosemite first. Or end up having to do some awkward file transferring later.
If you have not activated iCloud Drive, do one of the other things and activate it later. No reason to go through the migration, which can take a while, twice.
