Red Hat Enterprise Linux,2SKT 3Yr PREMIUM SUB - what do I have with ?

Dear Community,

I work for a DELL EMC partner.
A poweredge server R740 was shipped with :

1)Red Hat Enterprise linux 7.4 Factory Install,x64,Requires Subscription Selection

2)Red Hat Enterprise Linux,2SKT 3Yr PREMIUM SUB

Questions:
Who should do the registration ?
What kind of support to expect ?
Customer reinstalled the OS probably with RHEL 7.4
How to make sure he can get the expected support ?

Thanks for your help.

Best .

JJ.