It is possible to change certain task types after you have added them. This can be useful to modify the hierarchy of tasks and make edits in a work breakdown structure (WBS).
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.
Indent
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 (1.3.1.3) which is a sibling task to a Subtask 6 (1.3.1.2) and a subtask for Task 4, then it becomes a subtask for Subtask 6 and its WBS changes to 1.3.1.2.1.
Outdent
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 (1.3.1.2.1) which is a subtask to a Subtask 6 (1.3.1.2), then it will become a sibling task to a Subtask 6 (1.3.1.2) and its WBS changes to 1.3.1.3.
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.