with the IRS file form 8822. normally the refund is sent to the address on the return. then if you have given the USPS a change of address notice it should be forwarded but this could take some time. if the IRS gets and processes the 8822 before the refund is issued it should be sent to the address on the form.
https://www.irs.gov/pub/irs-pdf/f8822.pdf
