When a character joins a unit in Lance formation, they are placed on the outside of the Lance, in any rank, displacing one or more rank and file models to the rear rank as usual. Should you wish, a character can take the position of a command group model in the first or second rank of the Lance. In such cases, that command group model must be placed further back, on the outside of the Lance and will in turn displace another model to the rear rank of the unit.
If a character that has joined a Lance is required to 'retire' to the rear of the unit, they may be placed in the middle of any rank (not including the first or second). A character that has retired cannot occupy a position on the outside of the Lance and will no longer be within the fighting rank.