When converting lead forgot to tick "potential", now have contact and account, but no potential!

When converting lead forgot to tick "potential", now have contact and account, but no potential!

Hi,

Learning the system, wanted to convert lead.  Forgot to actually create potential, and converted.

Lead has been converted to contact and account, but not potential. 

Can't find a way to go back and edit this.

How do I add it to a potential???

Thanks