If you are in a WebApp method or an LJO, you can make a call to a linked model method by using the WebAppAccess callMethod(..)
method just as you would for a WebApp method, except that in the method name, you must specify the name of the Linked Model builder call as well as the method name.
Here is an example calling a method named doWork that takes a WebAppAccess and a string argument that is on a linked model:
In this example the actual signature of doWork is as follows:
public void doWork(WebAppAccess webAppAccess, String name);
Calling it through callMethod(..) automatically passes the WebAppAccess as the first argument.
Parent topic: Method and LJO method calls