On Bloomz you are able to transfer a student to a new class by adding the student's parent to your new class. Here is how you can do so:

• Create your new class
• Select the name of your old class on the left hand menu
• Click Settings in the top menu bar 
• Click Manage Members  
• Click the three-dot menu of the parent you would like to transfer
• Click Add to another group/class 
• Select your new class
• Click on Parent icon 
• The parent and student should be added to the new class.