How does answer deadline work?
If the organiser of the event requires attendance within a specific time, the host can set an answer deadline which will be visible to the invited. Members will not be able to attend or decline after the deadline has past without sending a message to the host.
On the other hand, administrators can change the status of all participants after the time limit has been reached. This process is described in “How do I change others answers”?
(If a member has not responded within the deadline they can still decline the event to clean up their app)