How to Call Widget inside a Function?

Hi, How do we call widgetBP inside a BlockClicked() function? Thanks in advance

BlockMesh->OnClicked.AddDynamic(this, &MyActor::BlockClicked);

void MyActor::BlockClicked(UPrimitiveComponent* ClickedComp)
{
	// Check we are not already active
	if (!bIsActive)
	{
		bIsActive = true;
   		// Change material
		BlockMesh->SetMaterial(0, Material);
	}
}

There are some post are available but very confusing and not resolved. Please help me to resolve this issues.