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If your instance is not listed it means , you will not be able to use this process to update to Ubuntu Pro. Ensure SSM is installed and functioning correctly and the instance is running, otherwise you won't be able to continue with this process.
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From the dropdown menu select the os type you want to change (in this case Ubuntu LTS) and select the ec2 instance(s) you want to update:
Select Nextand , then on the next page select , select Ubuntu Pro for the License type destination.
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