You may update the Label of an existing arm. To edit an arm, search for the study that has the desired arm, using Search[ |#id.elwy3aftu9nv]a[ |#id.elwy3aftu9nv]study.
Select the epoch that contains the arm whose label should be updated. System displays Edit epoch screen. Also, the list of existing arms are displayed in editable mode.
Update the label of arm and select Submit. System updates the label of arm and tree structure is updated to reflect the updated arm. Now select Save study.