If you want to log in to myCloud with a different, already existing Swisscom login, you can simply change the login. You can then log in to myCloud as usual with the new login and access your files and images.
To start the process Log into your myCloud account over www.mycloud.ch.swisscom.ch, go to “Settings” and click on « Do you want to use a different Swisscom login for myCloud?” ».
Then follow the steps below (please note that a Swisscom login mask appears twice during the process):
1. Start the process
2. In the first Swisscom login screen, enter in your pre-existing login information for myCloud 
3. In the second Swisscom login screen, enter in your desired Swisscom login
4. Confirm the change and you're done! 
If something should be unclear or doesn’t work despite these instructions, please contact us via the support form along with a screenshot of the error message so that we can solve your problem as quickly as possible.
Important notes:
- We recommend that you make this change in incognito browser mode.
- If you are already using the desired Swisscom login for another myCloud account, the change described here is not possible without deleting the myCloud account linked to the desired Swisscom login (follow these instructions: I have multiple myCloud accounts. How can I merge the accounts?)