yes if you have issues with the laptop you create a case and then they will schedule an onsite tech to replace the parts

Are you talking about laptop?

You can check your laptop serial no from HP website https://support.hp.com/my-en/checkwarranty/

It will show you all the details. This is example from my machine.

Warranty type Manufacturer Warranty
Service type Wty: HP HW Maintenance Onsite Support
Status  ? Expired
Start Date July 19, 2013
End Date August 17, 2016
Service Level Global Coverage
NextAvail TechResource Remote
NextAvail TechResource Onsite
Std Office Hrs Std Office Days
Standard Material Handling
No Usage Limitation
Next Cov Day Onsite Response
Standard Parts Logistics
Deliverables Parts and Material provided
Onsite Support
Hardware Problem Diagnosis
Service type Wty: HP Support for Initial Setup
Status  ? Expired
Start Date July 19, 2013
End Date November 15, 2013
Service Level NextAvail TechResource Remote
Std Office Hrs Std Office Days
Unlimited Named Callers
2 Hr Remote Response
Deliverables Initial Setup Assistance
If your warranty is covered with onsite support, they will come to you. Normally the guy from CTC global will come to replace the parts. Not directly from HP or Dell.

all HP are onsite service at the moment, as their service centers are closed.

However, there are no such thing as complete 1-1 exchange except for printers.

all models, even those purchased before they started the onsite service will have onsite service as there wont be service centers to service them otherwise.

just call and arrange a service and it should take just 2-3 days for normal consumer models.
1-1 exchange may be available for certain enterprise models, but typically even commerical laptops only have 1-1 for parts, not the whole thing.

onsite service, bro, not pick up.

They will confirm your case, log case, arrange a tech and send parts+tech to repair your device within 2-3 working days.

ie. you'll get your device functional within 2-3 days depending on your location, parts availability, face.

Normally they will come on next business day depends on the spare part availability.

who told you told information ?

end user also can dealing with Manufacturer HQ office support directly incase you are not aware , even bought from retail shop

CN case is last resolving after 1 to 1 

so far so good if they can help you identify the problem

Dont worry, after he replace the parts, he will ask you to check.