I have actually contact DELL regarding to this International Warranty service, and this is what I have received from DELL:

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If your notebook requires repair services at overseas country, you SHOULD contact DELL at your home country (The country you purchase your notebook) to lodge the service and inform DELL you are at overseas, DELL will transfer this job to the country where you are and send the technician to you for service.

If you cannot reach to DELL service hotline at your home country, you can alternatively ring DELL US support. However, it is highly recommend to ring DELL at your home country first. (Which means you need to pay International call charges to get your notebook repaired)
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That was clearly written on DELL International Warranty information sheet, and I was also sent a copy from DELL.