When defining the action flow of your action, you can split this action flow into several actions paths, depending on the evaluation of an expression; only one of these actions paths is executed. This behavior is implemented through the Switch element which you can drag onto your canvas from the Action Flow Toolbox.
Each action path is selected when the associated condition is true. The condition for each path is specified in the Options property of the Switch element. These must be Boolean expressions. The number of options is the number of possible paths minus one, which corresponds to the default path, labeled as Otherwise.
To edit these conditions, simply type the condition directly in the Condition Lnk x property or use the Expression editor.
To quickly launch the expression editor, simply double-click on the Condition Lnk x property or in the Switch element, in the action flow.
In the Action flow, each action path is labeled, automatically, with a number (1, 2, etc), except the one labeled with Otherwise, which is the default path. The labels 1, 2, etc represent the order by which the conditions are evaluated, therefore it is very important that you label the paths correctly. When a condition is evaluated as true, the algorithm stops. If all the conditions fail, the Otherwise action path is selected.
If you want to change the priority of the conditions, simply change the labels, by right-clicking on the Switch connector and selecting the Move Priority Up or Move Priority Down option. These options are not available for the Otherwise connector, which must be changed explicitly.
The Switch flow must follows this rule, otherwise an error message is presented and the eSpace is not valid:
There must always be an Otherwise path;
The conditions associated with each action path must return a Boolean value.
Switch Properties | Action Flow Toolbox