If you are adding the contact information of what you think is the plaintiff, and later realize the contact information is not for the plaintiff, you will most likely add the actual plaintiff as a related contact instead of deleting all of the gathered information and starting over.
For example, if a father is providing his contact information and you later find out that he is calling about his son/daughter who was in an accident, you should continue to add the child's information in the Related Contact screen (pictured below).
The solution is simple - After you finish gathering the desired information to complete the lead, click Create & View Lead at the bottom of the Add New Lead screen.
Go to the contact tab, click the Other Options button at the bottom of the the Related Contacts / Additional Plaintiffs section, and click Swap with Lead Contact.
Now the original related contact and lead will swap. The previous lead will now be the related contact. The other gathered information (Incident Details / Marketing Information) will remain the same.