If you mean two account playing on the same xbox then yes.
The highest rank in Halo: Reach is Inheritor.
Inheritor is the maximum rank so far in halo reach
earn it.
Rank up to Lt.col in halo reach
You try and get another rank
You get it when you reach commander.
In Halo Reach I think that the main objective is to rank up in different levels, upgrade your armor or just to have fun and kill people or the Covenant.
It is unlocked at the rank of Colonel on Halo: Reach and costs 1,200 CR
Rank up. There are no shortcuts.
It's a rank.
you need to be the rank of captain
Inheritor.