Accept any case class which extends a trait as argument in scala

I need a function to accept any case class which extends a trait. To give an example

Suppose there is a trait

trait Action {
    def execute(param: Parameters)
}

And following parameters can be passed depending on what type of action it is

trait Parameters
case class A(x: String, y: Double) extends Parameters
case class B(x: Int, y:String, z: Double) extends Parameters

User should be able to specify what it wants as parameters

class Action1 extends Action {
    override def execute(param: A)
}

class Action2 extends Action {
    override def execute(param: B)
}

and while calling

def run(t: Action) {
    t.execute(new A("a", 1.0))
}

How to achieve this? When I implement Action1, it says I will get error that we cannot override because trait says execute method accepts Parameters, but while overriding, we want a class which extends Parameters.