You can easily switch ownership of your team to a different person by inviting them into your team and, then, promoting them to Head Coach.
Please either invite the new coach to your team, or ask them to join. Once they are a member, go to the Classroom app and, on the Home page, look for their name in the team roster. Click on the 3 dost menu next to their name, and use the "Promote to Head Coach" option.
If you need to just add a secondary coach to the team, you can use the "Change Role" option to promote members of your team.