Does Seller(A) have to sign the Assignment contract too?? Wholesaling Help*

[Ciera Yorty]

   I've been learning everything I can about wholesaling and am stuck on this. I'm aware that both the seller and I need to sign the purchase agreement. But Is it important for them to also sign the Assignment sheet between myself and the End Buyer? I've only heard this recently in a book I read, and by a closing agent from a title company. I wouldn't want to get turned down by escrow day of closing, for not having the seller's signature on the assignment. Maybe it's about how transparent you want to be?