It depends on the situations. When you talk with your friend on the phone, people usually say " 就这样啦,拜拜”, which seems like " that's all, (my friend),bye". If you meet someone and say goodbye, you could just say " 再见,下次再聊". The properly translation is ' see you and talk later' or just 'Have a nice day'. I know, it might be hard to understand, but it's just a way to express that we are going to finish the conversation and say goodbye to each other.