Greetings @Asmov,
Very glad to see you back in PRO!
First thing you might need to know is that you are allowed to own until 4 accounts in PRO.
So your first account has no need to be deleted at all.
Then you can proceed yourself into exchanging between your accounts!
Please, be aware, that you will still need to be in the same pokecenter with both of your accounts, and also with the 4th badge of Kanto (owned by both accounts)
It means that your old account would need to get all the Johto badges and reach the pokecenter where your new account is.
Then, you will be able to trade between your accounts.
And, at last, if you transfer Johto Pokemon in your fresh new account, these pokemon will be locked into your pc until you reach Johto!
Please understand that we must deny your request about transfering back from one region to another, because it would be unfair towards other users who were rejected in the past.
I wish you a great new journey!
Kind regards
RockyRaccoon