There isnt one. You have to request for a b- billet and its really up to your current manager if they want to lose you. i found that allot of managers gatekeep special roles and there is definitely favorites and tenure to contend with to get them but if generally you'll get them so long as you aren't transferring departments. Note that most of these roles wont increase your pay.
I applied through other source. I interviewed at Amazon (Richmond, VA) in May 2020
Interview
Completely brainless, easy and if you can't get hired here, give up. You go in, they give you a drug test, they basically look at your background and give you an offer. Seriously it could not possibly be easier.
No interview, just submitted application online, went to a hiring appointment with 2 types of identification (ID and SS card) and took a mouth swab job test, then got emailed with a start date.
I applied online. The process took 1 day. I interviewed at Amazon (New Westminster, BC) in Jan 2021
Interview
Walked in. They asked me what shift I wanted. Took my picture and sent me on my way. I started less then a week later. The lines for the interview were long but the hey had a lot of interviewers