No viable conversion from 'Class *' to 'Class' C++

I feel like this should be simple but for whatever reason I can't get it to work.

I'm trying to create an instance of a class that can be passed into and edited directly by other functions.

For example:

main()
{
    ClassFoo foo = new ClassFoo();
    someFunction(foo);
}

void someFunction(ClassFoo& f)
{
    f.add("bar");
}

The problem is, when compiling, I end up with this error.

no viable conversion from 'ClassFoo *' to 'ClassFoo'
    ClassFoo foo = new ClassFoo();
             ^    ~~~~~~~~~~~~~~~

It also says that other candidate constructors are not viable, however in my ClassFoo class I do have a constructor that looks like this:

ClassFoo::ClassFoo()
{}

So how would I be able to accomplish editing the ClassFoo variable in functions?