How to refresh Api authorization token using Alamofire & rxSwift?

Question

I try to manage rxswift & Alamofire to get response.
These functions get response successfully when token is not expired.
But when the token is expired, I don't know how to refresh token and then retry to get response using new token.
What should I do to refresh token and retry?
I also read Alamofire documents, and I find "RequestAdapter" and "RequestRetrier".
Should I use RequestAdapter & RequestRetrier in my case?
But I dont know how to use them in my "getRequestJSON" function,
or have any good idea to refresh token and retry.
Thanks.

func get(_ callback: @escaping (JSON) -> Void) {
let url = "http://106.xx.xxx.xxx/user"
self.getRequestJSON( .get, url: url, params: [:], callback: { json in
    callback(json)
})
}

func getRequestJSON(_ method: Alamofire.HTTPMethod, url:String, params:[String:Any] = [:], callback: @escaping (JSON) -> Void) {

var headers:[String:String] = [String:String]()
if token.isEmpty == false {
    headers["Authorization"] = "Bearer \(token)"
}

let configuration = URLSessionConfiguration.default
configuration.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
configuration.timeoutIntervalForRequest = timeout

_ = SessionManager(configuration: configuration)
    .rx.responseJSON(method,
                     url,
                     parameters: params,
                     encoding: ((method == .get) ? URLEncoding.default : JSONEncoding.default),
                     headers: headers)
    .subscribeOn(SerialDispatchQueueScheduler.init(qos: .background))
    .subscribe(onNext: { (r, data) in

        if r.statusCode == 401 {

        //token fail 
        }            

        let json = JSON(data)

        if json["status"].stringValue == "successful" {

            callback(json)
        }else {
            callback(json)
        }
    }, onError: { (error) in

        callback(JSON(error))

    })
    .addDisposableTo(ResfulAPIDisposeBag)
}