Delegating is a good thing! To add an additional admin to your paid account, log into the account and click "Tools" on the left side of your account page. Click "Manage Administrators" to view current roles, edit roles, add new roles and assign admins. The subscription level you have will dictate the number of additional admins you can assign. View those plans here.
If you want Haley to manage the cotton candy sign up, you will add her as an admin and then you can go back to the sign up and designate her as the contact person at Step 1 for that sign up under "Advanced Settings." If Bill throws his back out again and can't spin the sugar, Haley will get the email about it.