If you have prior year tax unpaid, any refund will go to that tax liability.
You can't amend to get it back, but you might consider adjusting your withholding so there is not as much of a refund next year. Your paychecks should be a little larger. Perhaps you can budget so much a paycheck to a savings account and "Pretend" the savings account is a refund at the end of the year.
HERE is an IRS link about refunds and installment agreements