I say, and with God's success: It is to pray the prayer at its last time and wait for the following prayer and pray it at its first time. This is how the action of the Prophet Muhammad (peace be upon him) in combining prayers is understood, as he prayed Dhuhr at its last time and Asr at its first time, and he did the same with Maghrib and Isha. Thus, it becomes a combination of actions rather than times; as narrated by Aisha (may Allah be pleased with her) who said: "The Messenger of Allah (peace be upon him) used to delay Dhuhr and advance Asr, and delay Maghrib and advance Isha while traveling." This is explained in Sharh Ma'ani Al-Athar 1: 164, and Musnad Ahmad 6: 135, and its chain is good. See: I'laa Al-Sunan 2: 85. And Ibn Abbas (may Allah be pleased with them) said: "The Messenger of Allah (peace be upon him) prayed Dhuhr and Asr together in Medina without fear or travel." Abu Al-Zubair said: I asked Sa'id why he did that, and he said: I asked Ibn Abbas as you asked me, and he said: He wanted to not burden anyone from his nation." This is in Sahih Muslim 1: 490, and this can only be in a figurative combination. See: Tabyin Al-Haqaiq 1: 89, and Allah knows best.