var request: [String: Any] = [

    "Token": "Token",
    "Request": [
        "CityID": "CityID",
        "Filters": [
            "IsRecommendedOnly": "0",
            "IsShowRooms": "0"
        ]
    ]
]
//
print(request)

["Token": "Token", "Request": ["CityID": "CityID", "Filters": ["IsRecommendedOnly": "0", "IsShowRooms": "0"]]]

if var requestVal = request["Request"] as? [String: AnyObject], var filters = requestVal["Filters"] as? [String: String] {
    filters["IsShowRooms"] = "1"
    requestVal["Filters"] = filters as AnyObject
    request["Request"] = requestVal
}