Write a question about the following article.

I cut my trip short , called her doctor , and found out that she 'd be having emergency surgery at noon to drain the fluid . I make arrangements not to be at work , so I could drive down for her surgery . My aunt calls me at 5 am and tells me the surgery got moved to 6 am , so I was unable to make it down in time . After talking with my mom 's nurses I found out she did n't need her chest cracked open again .

Question:
What may be the reason for plans suddenly changing ?
Available choices: [I] The doctor did n't know what he was doing .; [II] None of the above choices .; [III] The nurse got the results confused .; [IV] The body has it 's own plan .;