回複：我認為不需要寫信cancel你的H4延期，因為並不會影響後一個申請

But I think if the previous H4 is not proved, they will not consider the next F1 application. Plus, if the F1 is proved in the first, I am afraid the H4 extension possiblly granted later, then the F1 will expire and covered by new H4 extension.

Am I correct? Thank you.