The first stanza of the popular Friday-night song "שלום עליכם" calls angels "מלאכי השלום מלאכי השרת מלאכי עליון" (or, in other versions, just "מלאכי השרת מלאכי עליון"). The other stanzas call them merely "מלאכי השלום מלאכי עליון". Why the change? That is, why does the first stanza and no other call the angels "מלאכי השרת"?
Rabbi Shlomo ben Eliyahu suggests that based on the Chazal that on Friday night 2 angels escort everyone home, and then if the table is set and prepared the good angel blesses the household that it should be the same in the coming week. The bad angel is forced to respond Amen. Therefore at first they are Malachei Hasharais and then when the 2 angels make peace they are Malachei Hashalom.