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Create a flow, or edit an existing flow.
In the step after the one you want to make optional, add two or more rules to transition from the previous steps.
Add a rule to transition from the previous step, as usual for a basic flow.
In the same step definition, add another rule. This second rule should be a transition from two steps back.
For example, in a three-step flow where step 2 is optional, create two transition rules in step 3: (1) transition from step 2 and (2) transition from step 1.
Complete the flow definition.
Here is an example flow with an optional second step:
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For more information about flow transition rules, see Understand flow definition conditions.