The Gemoro (Eruvin 43a) assumes that Eliyahu Hanavi cannot appear on Shabbos or Yom Tov, because of the Issur of Chutz L’tchum. (if Issur Techumin is Lemaloh Meiasarah )
How can we say at a Bris, on Shabbos & Yom Tov “Zeh Hakisei Shel Eliyahu—Amoid al Yemini- ?
The Shu”t Chasam Sofer (Chelek 6-98) explains that there are two parts to Eliyohu Hanavi. His Guf (body) which is resting in Gan Eden Hatachton, in this world. The other part is his Neshama, which went up to heaven and serves as a Malach.
At a Bris he appears as a Malach (Malach Habris) from heaven. A Malach is not
obligated to keep the Mitzvohs. There also is no Din of Techumin from heaven to earth
(Tosfos 45b dh. Leima) .
When the time will come, Bimeheiro Veyomeinu to bring us the Besura of Higia Z’man
Geulaschem, Eliyohu Hanavi will appear with his Guf & Neshama. at this stage he is like any Yid who is Mechuyav in Mitzvohs . He can’t come on Shabbos & Yom Tov from Gan Eden Hatachton which is Chutz L’tchum.
With this we can answer a famous kashye:
Why by a metzia we say Moonach ad Sheyovy ELiyahu and Teiku is the Roshey Taivos for Tishbi Yetaretz Kushyos Uboyos . It should be Eiku - Eliyahu Yetaretz Kushyos Uboyos.
Tishbi Yetaretz Kushyos Uboyos will be with his Guf, therefore
we don’t have the problem of Lo Bashomayim Hie
Moonach ad Sheyovy ELiyahu is just a matter of who it belongs to which someone from shomayim may say
Those who believe that E. Hanavi appears at the seder,
it can only be the Neshama (Guf can’t come from chutz l’tchum)