关于广州领事馆移民签证面试延期的问题

8老师好！ 我帮我妹一家3 口申请来美， 刚收到移民面试通知。因为孩子正在大学上课期间不可以请假，希望领馆能延期面试。但是在移民局网站上有一段说明如下：

Rescheduling or cancelling your interview

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If you are unable to attend your appointment, please visit ustraveldocs.com. There may be a significant wait before the next available appointment, so please attempt to attend the date already assigned. For some family-based and employment preference visa categories, a visa became available within the month you have been scheduled by NVC. DV applicants should be aware that visas are numerically limited and must be issued by September 30 of the program year. There is no guarantee that a visa will still be available on the date of your rescheduled interview. Please carefully consult the Visa Bulletin before you decide to reschedule you interview.

Please note: You need to register your original NVC/KCC appointment online before you can reschedule it. Rescheduling is only possible on a date after your assigned appointment.

 

8老师， 我不能完全明白以上这段文字说明。我担心如果申请面试延期，我妹一家不但会失去这次visa 的机会，以后可能不会再有下次visa的 机会了，移民的机会可能就会失去了。请帮我解释上面这段文字。因面试延期而失去签证的risk 会很高吗？

 

非常感谢老师帮助解答。