You can use the XML Schema Namespaces dialog box to easily set a target namespace and define namespace mappings for a newly created XML Schema. In the Design mode these namespaces can be modified anytime by choosing Edit Schema Namespaces from the contextual menu. Also you can do that by double-clicking the schema root in the diagram.
The XML Schema Namespaces dialog box allows you to edit the following information:
Target namespace - The target namespace of the schema.
Prefixes - The dialog box displays a table with namespaces and the mapped prefixes. You can add a new prefix mapping or remove an already existing one.