SynchUp Login Difficulty - Unable to change default login ID

I bought a SynchUp for my daughter this morning and successfully paired it with my phone. Then I tried to configure the app on my wife's phone. I started by logging into the app on her phone with my account and stopped mid-setup realizing that I should create a separate account for my wife.

Now every time I try to log into the app on her phone it defaults to my log-in ID. I can select the "not me" option at the bottom and then use her credentials but it never allows me to change to her credentials as the default so that future app use is easier / faster. I have tried logging out using both her and my credentials, rebooting the phone, disabling cloud saves and uninstalling / reinstalling the app - my credentials remain default.

¡Ayuda!