If American Express does not need to gather more information in most cases they will issue an Immediate Chargeback.
Generally speaking, a Chargeback is a final ruling and there are no chances to remove it unless you submit a “Chargeback Reversal”
If you submit a reversal and your reasoning is compelling, American express may opt to remove it on your behalf. This is not generally the case, so it’s very important to PREVENT the Chargeback from happening at all.