Getting a seller's price lower when already under contract.

[Joshua Johnson]

I'm looking at purchasing a house in NC. So far, I have a good relationship with wholesaler who introduced me to the seller to see if he was willing to go lower on the purchase price to where I need him to be to justify the numbers. 

Assuming I do get him to agree to a lower price, what would the process be to then fix the wholesaler's contract. Would they then agree to the lower some to fix their agreement, and then I sign the assigned contract with the wholesaler?

As I mentioned, so far it's a great relationship with everyone, and I'm not trying to circumvent the wholesaler at all, just trying to get the numbers to work on my end to flip so everyone wins. 

Any insights would be greatly appreciated!