CPFP (Child Pays For Parent)
This is a proposed method of 'unsticking' transactions with small fees that have difficulty getting included into a block.
One of the TxOut for a transaction (which we will call "transaction P") will be the sender's address for receiving change, so you can create a new transaction (which we will call "transaction C") that has the TxIn for this TxOut. In transaction C, the amount of fees is sufficient enough for both transactions.
Miners who find the fee for transaction C attractive include C in a block, which means that C's parent transaction P must also be included in the block. As a result, if the fee for transaction C is large enough, both P and C will be authorized.
Of course, if there are no miners willing to handle this type of transaction, it is not worth doing, but there is at least one mining pool at the moment willing to do it.