At the start of season 9 Riot released a position queues on NA and KR and is planning to add it to every sever after split 1, around late March – early April. You can read and watch more detailed information about that here: https://www.youtube.com/watch?v=tydJwdQRMqs
TLDR is that each position that you can play has separate ranking. So all players now have 5 rankings for top, mid, jgl, bot and support. When you rank up your main position some of the LP will splash on your off role positions. E.G. you gained 20 LP for main role mid +6 will splash on your second highest position jungle and +2-3 will splash on other roles. Splashing LP can’t trigger promotion at the moment, but they are still introducing new changes so it might in the future.
Instruction for our elo boosters:
So how should you proceed if you are doing S2->G4 for mid role and you got an off role? Whenever you get off role you should either just dodge the game if it’s a first time this happened, ask for a switch in champion select (System should detect that you switched positions) or just play the game and finish X amount of games from the target elo where X is the amount of games you were forced to play off role. You should notify our customer support how many games you have played off role as well as your customer.
Keep in mind that you shouldn’t dodge more often than once a day to prevent unnecessary LP loss to the customer.