Disclosed are double-stranded nucleic acid agents that can deliver a therapeutic oligonucleotide within a biological sample, and methods for using the same. In one embodiment, the double-stranded nucleic acid agent comprises a first strand comprising a first RNA region, and a second strand comprising a first DNA region, wherein said first RNA region and said first DNA region are hybridized as a RNA/DNA heteroduplex. Said first strand further comprises a nucleic acid therapeutic oligonucleotide region that is capable of being cleaved from at least one nucleotide in said first RNA region. Methods for using the double-stranded nucleic acid agents include methods for delivering the therapeutic oligonucleotide as a single strand by cleaving it from at least a portion of the first RNA region. The methods further include delivering the double-stranded nucleic acid agent and thus the therapeutic oligonucleotide to a target site within the body of a treatment subject.