Which amendment spells out who becomes president elect in the event of death of a president elect?

The 25th amendment outlines the line of succession in the case of a death in the executive branch. This outlines that in case of the president's or president elects death, the vice president will take over command. From there, the vice president will nominate an individual to take his/her role as vice president. This nomination must be approved by a majority vote from both the US House of Representatives and the US Senate.