How can I add a Participant List to a new SignUp without sending invitations?

There are a few ways a person can be added to the Participant List of a SignUp:

1. You send them an direct invitation
2. They use the Shareable Invitation link and sign up
3. You, or another organizer, assigns them a Spot manually.
4. You invite them from a prior SignUp's Participant List of Contact List. Here's how

While it's NOT possible to add people to the Participant List without inviting them in one of these 4 ways, you CAN keep a "copy" of a Participant list, stored in a Contact List. Please see: How Do I Import Emails or Create Contact Lists?

Once you've created a Contact List, you may:

• Send a message to people on the Contact List using Advanced Messaging (in the My Tools tab). Learn more here
• Invite people from the Contact List to a new SignUp. Here's how
• NOTE: The Contact List is owned by the SignUp account holder and is NOT transferable. 

See also: What's the Difference Between a Contact List and SignUp Participants?