Unfortunately, it is not possible to change the publisher of an existing virtual machine (VM) in Azure. The publisher setting is associated with the image used to create the VM, and once the VM is created, the publisher cannot be changed.
In this case, the only option would be to create a new virtual machine with a Canonical-provided image and transfer your data to the new VM. You can then delete the original VM created with the ntegralinc image.
Let me know if you need any assistance doing this or if you have further questions.
Please don’t forget to "Accept the answer" and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.