Get the transfer code
Go to the container you want to transfer and on the main info page on the top menu you will see a button labeled
Transfer code. Once you click that button you will get a code to copy and use on the account that will get the container.
Just copy the code you are shown, it will look like this.
On the new account enter in the code
On the main container list click on
Receive transfer at the top of the page, enter in the code and it will be moved to that account.