The unit's Standard Bearer, Musician, Champion and any characters within it, must be placed in the front rank. When the unit turns round to face the side or rear, its Champion, together with the Standard Bearer, Musician and any characters in the unit, are automatically rearranged into the new front rank.
Except, as discussed elsewhere, these special models, including any characters that have joined the unit, are always positioned in the front rank, with the Standard Bearer in the middle. Only if all the character models cannot fit into the front rank alongside the Musician and Standard Bearer are they placed into the second rank. Characters in the second rank cannot take part in close combat in any way unless they are directly engaged, via a flank charge for example.