Hi, Harald. Since your current email address is already linked to an account and one email can be used for only one account, it is possible to register another account on the same device, using a different email and different google ID. A new email address has to be added in "Accounts" -> "Google" on your device, and the same new google ID should be used when downloading the IO app from the Play store, after the current app has been previously deleted. If you are not already familiar with changing accounts, you might find helpful the steps in the link below. Should you have any other questions or difficulties, please reply to this thread and I will be happy to further assist you.
http://www.wikihow.com/Change-Your-Google-Sign-in-on-Android