To modify a railing

You can modify railings, handrails, and guardrails.

Select the railing element for modification.
The ribbon activates Modification > Modify Selected tab.
Select (Modify Properties).
The Modify Railing dialog is invoked.
Use the Modify Railing dialog to modify settings to selected railing.
When done, click in the view to accept the changes.

Besides changing a railing to another catalog type, you may use the Railing Construction Settings to modify one or two railing settings.