It wont work like that, the client will always use an unspent transaction outputs (
UTXO) to make a new transaction.
In your case, the second transaction only spent the unspent output (
change) of the first unconfirmed transaction because there's no other UTXO to use.
Otherwise, it will be displayed as "
insufficient balance".
jackg's method is the simplest, it only involves copy-pasting strings or scanning QR codes,
but it's riskier than BitCryptex' link because it involves exportation of private key(s).
But the transaction was now confirmed.