Saving reference to a mongoose document, after findOneAndUpdate

I feel like I'm encountering something completely simple, yet can not figure it out, will be glad, if you can help me.

I'm using mongoose + socket.io as CRUD between client and server. As I'm using sockets, there is a private scope individual for each client's socket, in which, for future use without making db find calls, I would like to store a reference of mongoose document, that I once found for this user.

One client is creanting a Room:

var currentroom;

client.on('roomcreate', function (data) {       
   currentroom = new Room({
      Roomid: id,
      UsersMeta: [UserMeta],
      ///other stuff///
      })
    currentroom.save(function (err, room) {
    if (err) console.log(err);
    else console.log('success');
    });
});

Then, whenewer I want, on another creator's call I can just simply

currentroom.Roomnaid = data;
curretroom.save()

And it's working fine, the problem is - I do not understand how I can get the same reference on not creating, but Room search, for the moment i'm using this for search:

 Room.findOneAndUpdate({ Roomid: roomid }, { $push: { UsersMeta: UserMeta}}, { new: false }, function (err, room) {
    if (err) console.log(err);
    console.log('room output:');        
    console.log(room);
    client.emit('others', room);
 })

The thing is, that in one call I want to:

1: find a doc in db,

3: send it to user (in pre-updated state),

4: update found document,

2: save a reference (of the current updated doc)

With findOneAndUpdate I can do all, but not saving a current reference. So, how I need to approach it then?