Adding assignments manually in the Spots tab of your SignUp's Organizer view only supports recording one name per unique email address. If you have Participants/family members sharing an email address, please use one of these options:
1) After making an assignment for the first Participant following these instructions, you may give the second Participant an assignment by clicking "Add a New Participant" and then entering the person's name and phone number, but leaving the email address field blank. (With this method, the Participant will NOT get a confirmation or reminder message and you will need to alert them of their assignments).
2) If you selected the option allowing Participants to Sign Up Others (such as family members or team members) in the Details tab when setting up your SignUp, you may then access the SignUp from the SignUp's Shareable Invitation Link and assign another person using the shared email address. NOTE: Be sure to logout of SignUp before clicking the Shareable Invitation Link and logout again after saving the new Participant's assignment.
Please also see: How do I sign up someone else (a family member, or my team or group members)?
3) If the Participant has a Gmail account, you may add an assignment for another Participant using the "+name" feature to clone the email address. SignUp will then view each email address/Participant record as unique, but all notifications will be routed to the original email address.
For example, if Sammy@gmail.com is the original Participant's email address and you want to make assignments for Sammy's Spouse, Ella and Child, Jo, then you would add assignments for Sammy+Ella@gmail.com and Sammy+Jo@gmail.com and all notifications would go to the Sammy@gmail.com address.