Query regarding H1B extension processing


i am currently on H1B visa and currently working with my employer since an year.

However, I will proceed on leaves for few months on H4 (already have a valid H4 and will apply for COS FROM H1 to H4).

in the meantime when I will be joining back my[b] H1B visa and Petition[/b] will be expired.  Please let me know if I need to apply for fresh H1B or I can file an extension as I have only consumed 1year from  6 years of duration (applicable to stay in USA on H1B visa).


Hi All
Kindly help me with your answer.