The following information will help you with domain name's renewal.
1. Please login your domain reseller control panel with your reseller account ID and password.
2. Please query the domain name at Manage Domain >> List My Domains on the left of navigation bar.
3. Please click the ns1 under DNS1 column on the page in front of you and proceed with it with instruction on the page.
Yes, we provide bulk tools for domain name servers update. Please check Manage Domain >> Bulk Operation Application in your reseller control panel. Please read notes first on bulk tools page before you submit bulk request.