Switching to Clay Paid Plan and Lookup Data Between Tables

I want to switch to a paid plan with Clay but I found that I can only use referrals only while signing up. Is there a way to delete my account and sign up again to leverage the referral benefits?

I have created a company table and a people table using the company table as base. Now I want to lookup some data from company table to the people table. How can I do it? I checked some articles but couldnt implement them properly.