# Invoke

Invoke

The Invoke activity requires a Partner Link name and an Operation as defined in the WSDL for that service. You can use the Quick Pick tree control at the right to select the Partner Link and Operation. For one-way invocations of the service, specify only an Input Variable; for request-response invocations you must also specify an Output Variable.

The checkbox labeled Use WSDL Message Parts Mapping provides an alternative to using variables for the request message.