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In your Workflow Designer, click on the Activity element icon on the left toolbar and then click on the Requestor swimlane. This will add an activity for your Requestor. To change the activity name from "Activity 1" to "Apply leave", click on the Selection element icon on the left toolbar and then double-click on Activity 1 in the swimlane. In the resulting dialog box, change "Activity 1" to "Apply Leaveleave" in the Name field.
Repeat the same steps for the Supervisor and HOD swimlanes, changing the activity names accordingly. Once done, your process should look like the figure below:
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