change in travel plan on visa waiver program

[superhuzzy]

hi my question is am in the state for 2 weeks vacation on a visa waiver program , is it possible to change my travel plan to a month even though am still within my 3mths

do i need to update the esta website or the i 94


thanks

[immihelp]

You can only stay till the date specified in I-94W form, not beyond that. You can not extend your stay beyond that date.