It doesn't work. It has scam written all over it. Even though you change wallet password, the wallet creator still has control over your private key and 12 word passphrase  and he can use it when even he wants to move all the fund he'll trick you to deposit later.

Here's how it'll pays out. He'll ask you to make some deposit into the wallet could be some few dollars or more to purchase the mining contract or what ever reason he'll give you then after few minutes your fund are gone and all contact with him will be lost so don't fall for it.


That's one of the reasons forum was created to alert newbies of possible scams. To stay updated with busted scams so you don't fall prey, pay a visit to the Scam accusation board regularly