I followed the below step in order to delete Workflow Manager.
- Leave the farm
- Launch the Workflow Manager Configuration Wizard as administrator. Only this one option will be listed.
- Copy the current configuration for later reference.
- Uninstall Software
- Workflow Manager 1.0
- Workflow Manager 1.0 Client
- Windows Fabric
- Service Bus 1.0
- Remove Databases
- Remove Service Application
- Workflow Service Application Proxy
- Remove application folder
- Delete folder C:\Program Data\Windows Fabric
- Delete folder C:\Program Files\Service Bus
- Delete folder C:\Program Files\WIndows Fabric
- Delete folder C:\Program Files\Workflow Manager
Note: If you’re recovering your workflow environment, your existing workflow won’t be deleted as they reside in content db. Once you setup Workflow Manager, check if you can see “SharePoint 2013 Workflow” and “Project Server 2013 Workflow” options in SharePoint Designer (I had to connect Workflow Application Service with the Web Application). Only then your existing workflow will show up under workflows in SPD.