Download PowerShell Module aztools.
Install-Module aztools
https://www.powershellgallery.com/packages/aztools/1.0.7/Content/public%5CRename-AzToolsAutomationRunbook.ps1
Run command Import-Module aztools
Then run the following command to rename Azure Runbook:
Rename-AzToolsAutomationRunbook -Name "Get-Devices" -NewName "Get-ADDevices"
Follow the prompts and select Subscription - ResourceGroup etc. and click Ok, if prompted.
This will change the state of your Runbook from Published to New. Run the following command to publish it again.
Publish-AzAutomationRunbook -Name GetADDevices
Follow the prompts to enter correct Resource group and Automation Account name. Or just package all those in a command and hit enter. Runbook will be published again.
Note: All the Execution history of the renamed Runbook will be lost, once it is renamed.