Can I only use only the returning leg of the two-way ticket?

Dear Sir/Madam,

My name is Tuan Hoang and my son's name is Duong Hoang. I bought the China Southern Airline return tickets for my son and I, departing Jakarta for Amsterdam on June 10 on CZ-3038 and returning to Jakarta from Amsterdam on June 26 on the CZ-308 (stopping over Baiyun on the way to Amsterdam as well as on the way back to Jakarta). Due to the change of my schedule, I will leave on June 12, instead of June 10. Is it possible that I can still use returning leg to Jakarta, while not using the departing leg to Amsterdam. I thank you for your reply.