Iter 179697769176 purchase ticket & hotel 7-18-14 Bejing. No visa yet. Can I reschdule next week?

I am US citizen with wife and son visiting Seoul for six weeks. Purchased tickets for wife, son an I for July 18-20 China. No Visa yet. Do I need visa for tourism visit for 54 hours? If so. Can I pay fee an reschedule for next week July 25-27, 2014 or get a refund. Iternary 179697769176. Skype cell 609-454-2525. We really would like to visit your country but we o not have our visa yet. We have our passports. Can you please help us? We are staying at DMC Ville here in Seoul, Korea