You can replace a component when you want to save the defined attributes, but you want to change the component type. For example, if you want to change the stitch type from Bartack to Flatlock, but you want to keep the attributes you already defined. This does not remove the component, rather replaces the component type.
To replace a component while saving the attributes:
Open the Seam & Stitch Manager.
Either select a predefined preset, or create a new preset.
Click the icon next to the Stitch you are replacing.
Select the type of stitch you want to replace with the current one. For example, select Stitch_flatlock_6m.
The stitch type is replaced and the attributes remain the same: