It is possible to only do a preauthorization of a credit card in the pay button (Charges and Payments tab).
By selecting Preauthorize only (check box), the card is not charged but only a preauthorization made.
When this is done, the preauth shows up as a line of type "PreAuth" instead of "Charge".
You can then decide to capture the payment at a later time or click "Void" to cancel the preauth.
To prevent double charging, the Charge button is disabled when a preauth has been made.
You need to either capture or void the preauth to enable it again.
The Charge Card dialog looks like this: