If 6 feet is going to sway your decision....sounds like you are getting cold feet.
Maybe a reduced price for a smaller yard is a more sensible rationale.
Get your original contract out and check if a survey was part of that contract...or a legal title....then get an attorney to send a love letter to the contractor with a price reduction....or just talk to the contractor first...make an aggreement on adjusted price and then send a letter confirming the change.

Did the contractor explain why this needed to happen? Why would a builder want to spend their money moving a fence unless there was a good reason? Were you satisfied with the contractor's answer? Does this have something to do with setbacks on the corner or neighborhood restrictions?

My other question as a Realtor who represents buyers and builders is "How important was that 6 ft in the yard?" Does this keep you from doing something in particular that is an insurmountable obstacle in purchasing this home otherwise? Or is there more?

Do you have a Realtor representing your interest?

Thanks for replying, Julie. Per the contractor, they would need to plant trees.

Steve,

This is more of a legal question and I am not an attorney. My question would be why the bulder wants or has to move the fence?