I am sorry for this late reply. I am not a Bitcoin Core user. But if you can can provide a guide for it, I can add it somewhere in the OP.
Ever since the release of Bitcoin Core 0.14.0 that the RPC command
bumpfee can be used - if one uses bitcoin-cli - in order to increase the fee that was used in a specific transaction (as long as it had Replace by fee enabled). In order to increase the fee by using CLI, per
bumpfee documentation[2], you have to respect the following command:
bumpfee "txid" ( options )
Usually people have trouble with the
(options] argument because it is classified as a JSON object ant when constructed incorrectly can output errors such as
"Error parsing JSON". An example of a command to bump the fee of an unconfirmed transaction in 40 sat/vB would be:
bitcoin-cli bumpfee <ARandomTXIDhere> '{"fee_rate":40}'If you're using the GUI version of Bitcoin Core, things are more user friendly - Ever since Bitcoin Core 0.15.0[3] there is a graphical option for a user to replace the fee of an unconfirmed transaction (assuming it has RBF enabled) by just going into the menu
Transactions -> Right-Click on the unconfirmed transaction -> Choose
Increase Transaction Fee and then choose the desired sat/vB rate.
[1]
https://bitcoincore.org/en/releases/0.14.0/[2]
https://bitcoincore.org/en/doc/0.21.0/rpc/wallet/bumpfee/[3]
https://bitcoincore.org/en/2017/09/01/release-0.15.0/
