using ead and changing job

[bir999]

i had an approved ead for last 15 months and continued to be on h-1b which will expire in a few months , for this reason and also my desire to change employers in a few months...i filled out an i-9 form
my employer has never dealt with immigration in the past
and we do not know what is to be done with a filled i-9 form ...is it to be sent to bcis ...or is it just to be kept in my employers records ..and in case i use ac-21 provision and change jobs ...how will bcis know that i am using ead

 

[jaxen]

kept at employer's records. USCIS will know that you have changed job if
1. Previous employer informs USCIS
2. You inform them in writing