There is a way to cancel pending transactions if you change your mind and choose not to complete the transaction. However, the only effective way to prevent an already (partially) signed transaction from not executing in the future is to execute an “empty” transaction at the same nonce. To create this empty cancellation transaction, you can click on the Reject button in the transaction details.
Then,you should sign with your connected signing wallet (eg Metamask or Ledger device). After doing this, you will see that there is a new transaction in the transaction list that conflicts with the original transaction that you are trying to cancel it.
To actually complete the cancellation, potential other signers of your Walliro account would have to confirm the cancellation transaction. You can do it by scrolling down to the transaction details of the canceled transaction and clicking the confirm button.
With the last signature that is required, you will be able to execute the cancellation transaction. This will require a small transaction fee.