If the bank lowers my principal loan during a modification, will it affect a future sale?

NO. The current balance when you sell is what you will owe.

Yes it can, depending on your modification agreement you may be required to pay back all or some of the reduction. make sure you read all the fine print on your modification.

it depends on the agreement you have with your existing lender.. but in general, most loan mod's that had principal reduction included in the modification has a disclaimer that if you sell the property within so many years, you have to pay back all or a portion depending on how long after the modification you decide to sell.. it's really up to the agreement you signed..I'm a Broker here in Scottsdale AZ and I only lend in Arizona. If you or someone you know is looking for financing options, feel free to contact me or pass along my information. William J. Acres, Lender411's number ONE lender in Arizona. 480-287-5714 WilliamAcres.com