Samourai is one of the only Bitcoin wallets to allow you to top-up the miner fee of transaction that has been sent to you. This can be useful if the sender included such a low fee that the transaction will take many days to confirm.
Step 1 - Tap the unconfirmed transaction
To top up the transaction fee of a received transaction simply tap the transaction on the Main Screen in Samourai. This will take you to the Transaction Details screen.
Step 2 - Increase Fee
On the Transaction Details screen, Tap Boost Transaction Fee to begin the process. You will be asked to confirm the new miner fee before the boost is attempted.
Step 3 - Wait for confirmation
Once you have sent the boost you will see a small transaction leave your wallet, this is the boost transaction. Both this boost transaction and your original stuck transaction should confirm within the next block.