Uses for change-type action?

[Keir Novik]

Well, thinking abstractly, what about units that have essentially the same
composition, but react or perform differently?  E.g., an infantry unit
that can change to "dug-in infantry" type, and back again?  The movement
and combat capabilities would be different for each type.  I could also
imagine "infantry mounted in halftracks" <--> "infantry with accompanying
halftracks", "fighters in an interceptor role" <--> "fighters in an escort
role", etc.

 - KN