After joining a Grand Company, you can do guildleves. One particular type I found in Gridania was
Kill 3 of these monsters under 5 minutes - kill as many as possible.
If you slay 3, you effectively fulfil the minimum requirements for the guildleve. However, the guildleve will not end until those 5 minutes have passed. If you kill more than 3, I think you get a bonus reward.
Is it possible to force the guildleve to end after I have fulfilled the minimum requirements? I'm not interested in the bonuses, and don't want to wait those 5 minutes.
I tried speaking with the guildleves NPC - can't remember what he says but it certainly doesn't end the guildleve. I also opened the quest log, but the options were about the difficulty or abandoning the quest.