Board Thread:The Quarters - Q & A/@comment-80.233.37.44-20181022213233/@comment-27659888-20190728210509

Fandom User, regarding your Party & Guild Data Tool, yes you can not leave a quest if it is pending (that is not started). The API will not allow you to. However you should be able to reject the quest. (The button still active) and leave. Another bug / feature in the API.

If your curious, you cannot Accept a quest via the Party & Guild Data Tool. Once you rejected the quest, it is rejected and you need to wait till the next invite.