@Dikesh Shrestha, Thanks for posting in Q&A.
Based on my research, if you already renamed the device but don't see its new name, the device might need to check in to Intune. Also, if you have an enrollment profile (iOS) that uses a Device Name Template, the device will be renamed but will revert to using the template upon the next sync with Intune.
And based on my testing, after I did the rename action to my device, I sync the device with Intune and restart it, after that it changes name successfully. So, please go to client device and open Settings > Accounts > Access work or school > find the account > expand the info page > Click Sync, after that wait for few minutes to see if the new devices name appears.
https://learn.microsoft.com/en-us/mem/intune-service/remote-actions/device-rename#rename-a-device
Hope above information can help you.
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