After each change, the PC must attempt a DC 15 Wisdom check; if the PC succeeds or is notified by an ally that witnesses the change, the PC is aware of their affliction. Once a PC is aware of their affliction they can attempt to have it removed. If the affliction is not removed after the PC becomes aware of it, the next change shifts their alignment to that of the were-creature and if this results in the PC having an evil alignment they may face repercussions from the guild. See page 178 of the Monster Manual for the rules for curing lycanthropy.
Each cure attempt costs the afflicted player one TU. The first attempt to remove it is always considered to be within three days of contracting it.
Phases of the Moon
Unless specifically stated in the adventure, the phase of the moon is determined in the following manner: the DM rolls a d10 before play begins. On a result of 1 the first day of the scenario is a night of the full moon (roll 1d3 to determine where in the sequence of three nights it falls as full moons always last three nights).