Parties in GXU, while still similar to those in GX, have been slightly altered with the revamping.
A party has a maximum of four members at any one time, with one person being the leader. With the new system, only the party leader can begin missions, accept quests in missions, report those quests, change areas and change channels.
Although it is the responsibility of the party leader to change areas in order to progress through the mission, all of the party members must be with a certain distance of the entrance to the next area in order for the leader to be able to switch.
All of the members of the party recieve a part of the experience gained, both for the nanobot and the character. Also, only parties are allowed to enter instanced areas (ie. "boss battle") as a group, without a party one must enter these areas by themselves.