An electronic device comprising: at least one wireless communication circuit configured to provide communication by using a a first radio access technology, RAT, and a second RAT; a processor operatively connected to the at least one wireless communication circuit; and a memory operatively connected to the processor, wherein the memory stores instructions that, when executed, cause the processor to: transmit at least a portion of a plurality of first data packets based on a first packet data convergence protocol, PDCP, detect a PDCP change from the first PDCP to a second PDCP by detecting a change between new radio, NR, PDCP and evolved universal mobile communication system terrestrial radio access, E-UTRA, PDCP, identify, in response to the detected PDCP change, at least one first data packet that is delivered from a PDCP layer to a lower layer and not transmitted to a physical layer, and when a transmission protocol of the at least one first data packet is a user datagram protocol, UDP, determine to reprocess the at least one first data packet by: storing the at least one first data packet in a buffer, changing at least portion of the first data packet to at least one second data packet related to the second PDCP by removing at least one first packet header from the at least one first data packet and adding at least one second packet header, comprising an identifier related to the second PDCP, to the at least one first data packet from which the at least one first packet header has been removed, and transmitting the at least one second data packet. at least one wireless communication circuit configured to provide communication by using a a first radio access technology, RAT, and a second RAT; a processor operatively connected to the at least one wireless communication circuit; and a memory operatively connected to the processor, wherein the memory stores instructions that, when executed, cause the processor to: transmit at least a portion of a plurality of first data packets based on a first packet data convergence protocol, PDCP, detect a PDCP change from the first PDCP to a second PDCP by detecting a change between new radio, NR, PDCP and evolved universal mobile communication system terrestrial radio access, E-UTRA, PDCP, identify, in response to the detected PDCP change, at least one first data packet that is delivered from a PDCP layer to a lower layer and not transmitted to a physical layer, and when a transmission protocol of the at least one first data packet is a user datagram protocol, UDP, determine to reprocess the at least one first data packet by: storing the at least one first data packet in a buffer, changing at least portion of the first data packet to at least one second data packet related to the second PDCP by removing at least one first packet header from the at least one first data packet and adding at least one second packet header, comprising an identifier related to the second PDCP, to the at least one first data packet from which the at least one first packet header has been removed, and transmitting the at least one second data packet. transmit at least a portion of a plurality of first data packets based on a first packet data convergence protocol, PDCP, detect a PDCP change from the first PDCP to a second PDCP by detecting a change between new radio, NR, PDCP and evolved universal mobile communication system terrestrial radio access, E-UTRA, PDCP, identify, in response to the detected PDCP change, at least one first data packet that is delivered from a PDCP layer to a lower layer and not transmitted to a physical layer, and when a transmission protocol of the at least one first data packet is a user datagram protocol, UDP, determine to reprocess the at least one first data packet by: storing the at least one first data packet in a buffer, changing at least portion of the first data packet to at least one second data packet related to the second PDCP by removing at least one first packet header from the at least one first data packet and adding at least one second packet header, comprising an identifier related to the second PDCP, to the at least one first data packet from which the at least one first packet header has been removed, and transmitting the at least one second data packet. storing the at least one first data packet in a buffer, changing at least portion of the first data packet to at least one second data packet related to the second PDCP by removing at least one first packet header from the at least one first data packet and adding at least one second packet header, comprising an identifier related to the second PDCP, to the at least one first data packet from which the at least one first packet header has been removed, and transmitting the at least one second data packet.