The nameservers for domain can be modified through Client's Area page. These steps are applicable for all domain including .my domains.

1. Login to Client's Area page
2. Dropdown Domains and select My Domains
   
   
   
3. Use the Search bar to filter the domain name
4. Click Manage Domain button align to the domain name
   
   
   
5. Make sure the Registrar Lock is disabled. Go to Registrar Lock tab and disable it
   
   
   
6. Change to Nameservers tab and tick Use custom nameservers then enter the new nameserver for the domain
   
   
   
7. Click on Change Nameservers to update the changes
8. Back to Registrar Lock tab to re-enable the registrar lock

You may need to wait up to 24 hours for the new nameservers to fully propagate. You may use below online lookup tools to monitor:

1. WhatsMyDNS

2. Whois myNIC