Hi @Panupol_Sonnuam, welcome to the community 
To search for an event using text and then update the event, you’d need to us two separate Google Calendar nodes. On the first one, you can search for events by using the Get All operation and the Query option like so:
This would return the id of your event which you can then use in the next Google Calendar node updating your event by adding a new expression like so:
Then picking the id in the expression editor:
Hope this helps! Let me know if you get stuck somewhere 