At this time, Clara can only process one scheduling action per email thread. If you need to make changes to multiple events — such as rescheduling your entire afternoon — you will need to submit a separate request for each one.
To do this, send Clara a new email with a unique subject line for each event you want to add or modify — or better yet, reply directly to the event invitation so Clara can easily find it on your calendar. Sending multiple requests in the same thread will result in Clara only acting on the first item.