Transfer Visa from F1 to B2

[cnse]

My husband is a Green Card Holder. Right now, I am pregant, so we want to transfer my Visa from F1 to B2 for half year. I just wonder which materials I need to hand in US immigration office and what I should mention in my letter to US immigration office.
Thanks a lot!

[kabkaba]

My suggestion, don't do it.
Talk to your school's DSO and ask them if you can take a break in studies. If you can't, try and take low/easy course load and maintain F1 status.