You can specify that workflow steps are executed only when specified conditions are met. Setting conditions can help you:

• Make a workflow more flexible - for example, you might want to install an antivirus program only on Windows VMs.
• Add an extra level of approval to a workflow - for example, if the user requests resource changes.

You can also make an entire workflow conditional by adding only a single conditional step to it.
http://www.embotics.com/documentation/index.html?manage_workflows.htm