Can I set up a second page to collect additional information on a second attendee?

Yes, you can. You can add a page break to create a multi page form. 

https://www.jotform.com/help/119-How-to-Create-Multi-Page-Forms

You can then add a condition in the form to skip users to the last page to submit if they opted not to add an attendee.

https://www.jotform.com/help/350-How-to-Skip-Pages-Using-Conditional-Logic