You can modify static parameters of library objects dynamically at model runtime.
To change a value of some parameter, you should call the automatically generated function
set_parameterCodeName(), passing the value you want to assign as a function parameter.
For example, to change the Capacity of queue object to 50, you should call queue.set_capacity(50);
You may ask - how can I know the code name of the parameter, I can see only labels like Arrival rate in the Properties view. To know the programmatic name of some parameter, we recommend you to refer to Library Reference Guide. There you can find the full description of object parameters. For example, to find the code name for Source's Arrival rate, open the help document on Source object and search for Arrival rate section. Here you can find the required name in the Syntax: row:
In this particular case the name of the function will be set_rate()
Please note that here we talk about static parameters, not dynamic ones. Dynamic parameters are evaluated each time they are needed, e.g. each time the delay time, the speed or other property of an agent needs to be obtained, so they do not have any persistent value, and it is meaningless to speak about changing values of dynamic parameters.