Find files old Microsoft OneNote folder on Ipad

Hello all,

I am a computer scientist for a school and i've a student with the following problem :

she has an Microsoft Office365 account with her OneDrive application installed on her ipad.

She's using OneNote to manage her notes. Normally, a OneNote file is stored in the local OneDrive folder and is synced to the cloud when there is an internet connection.

For a reason X, she never synchronized her OneNote files but she can open them on her Ipad, no worry. So the files are in her ipad but not in the cloud.

Now, the school changed all email addresses and of course, the Office365 account changed, too. When she creates a new OneNote file, it is syncronized but her old onenote files not. So we tried to find them to move them somewhere they can be syncronized but we dont know where they are stored.

The old link vs  the new link looks like that : 

We tried to do the following : 

Created a new onenote notebook (which is now syncronized in her onedrive) , open and old notebook and tried to copy/move the pages into the new one. This failed with the following message : notebook needs to be syncronized first ... 

Tried to find the files with the linux shell : 

One of her OneNote file is named 'History'

I tried to open a shell (I'm not a linux guru) and tried something like # find -name *history*

but nothing...

so I wonder how can I find these onenote files and how could I copy them in the new onedrive local folder to allow them being syncronized...

Thanks to all for your help

Best Regards