The twelve tribes of Israel are listed in several places in Scripture. Invariably the names on a later list differ from the earlier list. For instance, Simeon is absent in Deuteronomy 33 and Dan is absent in Revelation 7. Revelation has a later reference to the twelve tribes:
It had a great, high wall, with twelve gates, and at the gates twelve angels, and on the gates the names of the twelve tribes of the sons of Israel were inscribed (Revelation 21:12 ESV)
At first one might say the names on the gates would be the same as those listed in Revelation 7: Judah, Reuben, Gad, Asher, Napthali, Manasseh, Simeon, Levi, Issahcar, Zebulun, Joseph, Benjamin, and Dan is not listed.
The implication of Revelation 21 is each tribe would enter through the gate with the name of an individual tribe. For example, Judah would enter through gate with the name "Judah." Presumably Judah would not enter through one of the other 11 gates. However, if a tribe is authorized to enter, logically it should be able to enter through any gate, not just the one marked "Judah."
The concept of entering through any gate gives leads me to consider the "name" used to describe all tribes. For example, all tribes are sometimes called the "sons of Jacob" and other times the "sons of Israel" and if either of those names was on a gate, any son of Jacob or son of Israel could enter through that gate.
Does "names" refer to different individuals or does it refer to different ways to describe all tribes? Then if names are of individual tribes one would presume Dan is missing. If a name is one that identifies all tribes, one would seek to find 12 ways all of the sons of Israel can be described.