To convert the task in GanttPRO Gantt diagram maker, you have to click on the three-dots button on the right side of its name and select the corresponding option. In particular, you have three options: indent, outdent, and convert into milestone.
Converts a task into a subtask of a previous sibling task.
In this example, you can see that if we apply Indent for a Subtask 7 (188.8.131.52) which is a sibling task to a Subtask 6 (184.108.40.206) and a subtask for Task 4, then it becomes a subtask for Subtask 6 and its WBS changes to 220.127.116.11.1.
Converts a subtask into a sibling task to a previous task. This is a reverse process of Indent.
Thus, in the same example if we apply Oudent for a Subtask 7 (18.104.22.168.1) which is a subtask to a Subtask 6 (22.214.171.124), then it will become a sibling task to a Subtask 6 (126.96.36.199) and its WBS changes to 188.8.131.52.
Convert into milestone
Converts a selected task into a milestone. You can always convert a milestone back into a task.
It is also possible to convert a task into a milestone changing task type in Task settings.