Crew reroll token was removed from RuneScape after an update, but still exists in-game for those who had obtained it.
Crew reroll tokens can be obtained as a reward for completing 10 of Meg's cases during the Mega May event. It adds one set of five crew rerolls to be used. It cannot be redeemed if three crew rerolls are already owned.
This item cannot be used until the player has completed the player-owned port tutorial.