Moving from Shared to Reseller Hosting is an upgrade, not a fresh start, your existing sites and settings carry over onto the new resource pool.
Request the upgrade
From your account, choose Upgrade Plan, or contact sales if you'd like help picking a Reseller tier first.
Your existing sites carry over
Files, databases, and email on your current account move onto the new plan's resource pool as-is, nothing needs to be rebuilt or migrated.
WHM access is provisioned automatically
Root-level WHM, along with root SSH to the server, is available on the account as soon as the upgrade completes.
Set up white-label branding, if you plan to resell
Private nameservers aren't required, but most agencies set them up before onboarding their first client, see Set up white-label nameservers for your brand.
Create your first client account
Once WHM is live, see Create your first client cPanel account in WHM to start onboarding.
Billing
The upgrade is prorated the same way as any plan change, you're only charged the difference for the remaining days in your current billing period.