Unfortunately, no. Transactions within Circle are processed right away and cannot be canceled.
Circle requires you to verify your intent before adding money, cashing out, or sending money to someone else. You must confirm cashing out and sending money over your preset 24 hour limit by using two-factor authentication (2FA).
The only time you can cancel a transaction is if you have sent money to someone who does not have a Circle account, and they cannot sign up for Circle to pick up those funds. If that is the case, you can select the specific transaction from your transaction history in order to access the option to cancel it. As mentioned above, if they already have a Circle account it will be transferred to their account automatically.