Question: In Journey Builder where the Entry Object is Contact, i have setup event criteria to fire journey upon Creation or Updating a Contact. But once activated, the journey only fires up when a Contact is Created. 

Then i tried updating that Contact, but it is not being accepted in the Journey.

Journey settings is set to Re-Entry Anytime.

Is it possible to fire a journey by updating a Contact?

Thanks in advance.

Answer: 
The [documentation](https://help.salesforce.com/articleView?id=mc_jb_salesforce_data_event.htm&type=5) is a little misleading when it states: "The rule does not run when a record that previously met rule criteria is updated". Makes it sound like a record can't qualify again.

So for updated to work, the record needs to be updated from something different than the entry criteria condition, to something that equals the condition. 
For example, entry criteria is "some\_number\_field > 0". If the value is 1 for first entry and you change to 2, it wont trigger and re-enter. You would need to change that value to 0 to disqualify and then to 2 (or anything greater than 0) in order to qualify. 

To get around this I created a new custom field as a boolean on the object. Journey entry criteria is then set to "New\_Field = False". When I create the new object I set the field to "False" which enters the record into the journey. Then in the first step in the journey I set the New\_Field value to "True". When I want the record triggered into the journey again I set to "False" again.
Salesforce Data Entry Events are only triggered when a contact goes from a state of not meeting criteria to then meeting the criteria. Since the same contact that had already met criteria was updated, the event was not triggered. 

See link here:

"When a record is updated, the rule runs only if the record meets rule criteria after the update. The rule does not run when a record that previously met rule criteria is updated."

<https://help.salesforce.com/articleView?id=mc_jb_salesforce_data_event.htm&type=5>