Step 1: Go into the message thread you would like to view as your co-teacher.
Step 2: Click the '...' in the top right corner of the thread.
Step 3: Select 'View Chat As' to see all other teachers who communicate with the student.
Step 4: Select the co-teacher you want to view as.
Step 5: View the message thread as the other teacher and then select 'Switch View' in the top right when you are finished and ready to go back to your own view.