I posted on your other thread as well, but what Noodles just wrote above is correct...Bobbi didn't really "turn on you", but rather you guys were in the "Honeymoon Phase" of him just having come home...I didn't originally realize how short a period of time you have had him, I saw that he was a year and a half old and didn't read the entire story...So when you first brought him home Bobbi latched-onto you as the person in the new environment that he most-trusted in a totally new environment with new people where he was most-likely very anxious and scared...Now he's settling-in to his new environment, he has probably adopted his cage as his "territory" and considers it a "safe-space", he feels more comfortable in the environment, and now the :Honeymoon" is over...
Also, as I just read his age, he is likely also extremely hormonal right now, which is probably a good part of the biting, not only of you but of everyone...So he's got a lot going on, a new home, new people, new routines and schedules, and on top of all of that he's probably very hormonal (not only due to his age but also due to the time of year)...All 4 of my guys just went through or are still going through big molts, and my Green Cheek and my Senegal both are moody as all-hell right now...Tis the season...
So rather than Bobbie having suddenly "Turned on you", he's simply starting to settle-in, feel more comfortable in his new home, and now comes the time it takes to actually bond with and form a relationship with your new parrot, which is always going to take time, whether the bird is hand-raised, or a baby or an adult, it always takes some time with most birds for you to actually "Earn their Trust" and bond closely with them...
***What I suggest is that right now, today, you "Hit the Reset-Button" and start over with Bobbi, like you just brought him home today...Now that the initial fright/insecurity/discomfort of leaving his home and his Flock and moving into a new home with a new Flock is starting to pass, now comes the time to start earning his trust and really bonding with him...And this takes time, and it is going to take time with ANY BIRD you bring home, regardless of age. Again, they have the intelligence of a 3-4 year-old human toddler, so if you think about this that way, you don't just meet a 3 year-old toddler and have them immediately love you and trust you...Right now Bobbi doesn't have anyone that he trusts or that he is bonded to, so it's time to start slowly forming a relationship with him over-time...
Forming a bond with and earning the trust of a parrot is always going to be a marathon, it's never a sprint. We tend to want things to happen quickly because we automatically love our new birds, and we also tend to think of them like we do other pets, such as dogs. But parrots are not at all like dogs or any other type of pet in the way they form bonds with people (except maybe a pet primate like a Monkey or Lemur). Everything needs to go at HIS PACE and not at your pace...As already stated above, you started trying different bonding techniques with Bobbi, but only 5 days ago, and that's no time at all...I have worked at an Avian Rescue for years and years, and I always tell people who are adopting a parrot that it can take months and months of spending time with them every single day, and interacting with them both directly and indirectly for you to fully earn their trust and form a close bond with them (passive-interaction, meaning just having his cage in the main-room of your house where you spend most of your time, so he's there with you when you're reading, talking, eating a meal, watching TV, etc. but not necessarily directly interacting with him or talking to him)....
***There is a big difference between having a new parrot that you just brought into your home and your family just being willing to step-up for you or being willing to sit on your shoulder when you first bring them home, which is simply a sign that they are a hand-tamed bird, and gradually forming an extremely close, loving bond with them over time. It's very much like starting a new relationship with another person, like when you first meet your best-friend, and it's very much the same as when an adult human adopts a child. Once you put in the time and effort and you finally earn the trust of your new bird and bond closely with him and he with you, it's an extremely special relationship...So it's worth the time and effort, trust me...But you can't expect it to happen within a matter of weeks or even a month or two, and that goes for any bird you might bring home...
I read what you wrote about re-homing him potentially because you don't think he's a good fit for you, etc., and you're certainly are not the first person to feel this way after only having your new parrot for a week or two. In fact, I see people all the time at the Avian Rescue bringing in birds to surrender that they've only had for a month or less, or trying to bring back birds that they've adopted from us after only a month or less, simply because the bird isn't yet a cuddly, loving little bird, because it is still biting their hands, because it won't let them hold them or pet them yet, etc. Sometimes we can talk them out of it, sometimes we can't...I always tell them that it doesn't matter what bird they bring home from the Rescue, it's going to take the same amount of time to earn their trust and build the kind of relationship that they want to have with them. Some people adopt and surrender bird after bird after bird because they aren't instantly bonded to the bird in a matter of weeks...It's one of the reason their are so many birds in need of homes in Rescues and Shelters, and why so many are being re-homed on Craigslist and other sites...
So I would just take a deep breath, "Hit the Reset-Button", and just commit yourself to working with Bobbi and spending as much time with Bobbi as you can every single day. Make sure that his cage is located in the "main room" of your home, where you and others spend most of their time when they're at home and not in a spare-bedroom or back room away from "where the action is", because you want Bobbi in the room with you whenever you're reading, watching TV, playing video games, on the computer, eating your meals, etc. And spend as much time as you can directly interacting with him too, talking to him, reading books to him, etc. And little by little you are going to build a very close, strong relationship with him that is going to be very, very special...A Green Cheek Conure lives into their 30's...that's a long time that you're going to have him in your life, and that's why it takes some time to build a relationship with them...And once you do, it's forever...
. 
