How to Use a Function That Requires a Pointer Argument When Only Having the Name of the pointer?

Question

I'm working with structures in C where I've defined a doubly linked list and a function to add elements to the left of the list (list_add_left). The problem I'm facing is that I only have the name of the doubly linked list I want to add to, but the list_add_left function takes a doubly linked list as its first argument and not strings.

Here are my structure and function definitions:

List* list_init(char attribute) {
    List* new_list = (List*)malloc(sizeof(List));
    if (new_list != NULL) {
        new_list->size = 0;
        new_list->attribute = attribute;
        new_list->first = NULL;
        new_list->last = NULL;
    }
    return new_list;
}

void list_add_left(List* list, const char* color, const char* shape) {
    Node* new_node = create_node(color, shape);
    if (new_node != NULL) {
        if (list->size == 0) {
            list->first = new_node;
            list->last = new_node;
        } else {
            new_node->next = list->first;
            list->first->prev = new_node;
            list->first = new_node;
        }
        list->size++;
    }
}

I've also created instances of the List:

List* listRed = list_init('Red');
List* listYellow = list_init('Yellow');
List* listGreen = list_init('Green');
List* listBlue = list_init('Blue');

Now, if I want to add to listRed, how should I use the list_add_left function when I only have the string listRed?

I've tried the dereferencing operator (*), but it did not work. I also attempted (void)&listRed, but that did not work either.

Any suggestions on how I can achieve this?