dialogprepare and dialogstart paring?

In this spec I could not find a mention either way on this.   If I prepare a dialog and get an dialog id, can start the dialog and then after the dialog exits, use the same dialog id to start that dialog again without doing a dialog start?

Prepare -> Start -> Exit -> Start -> Exit
-or-
Prepare -> Start -> Exit -> Prepare -> Start -> Exit
-or-
Either and it is up to the implementation?

Ross