Using Electrum?
First this is for information only, not a way of illicit activity encouragement.
Try this:
1. Open your electrum wallet while online to sync and get the correct balance to make sure that all available inputs are valid.
2. Display 'coins' tab by clicking "
View->Show Coins", then disable your network connection (
you can do this online, but it's safer offline).
3. Enable "
Use Replace-By-Fee" and "
Edit fees manually" from "
Tools->Preference->Fees tab".
4. Create the 1sat/byte transaction by specifying which input to use from the 'coins' tab, right click to an "
output point(s)" with enough balance for your transaction and click "
spend".
5. You'll be transferred to the 'send' tab, input the test recipient's address and amount and the fee rate '1',
6. Click "
preview" then Click "
Sign" (
type your passphrase)
It must be signed.
7. Now Click "
Copy" and paste it on a text file, name that text file with something like "
1sat/byte signed RAW tx".
8. Close the preview window and select 'yes' when prompted to 'not to save'.
.
9. Now repeat 4-7 using the same "
output point(s)" but this time, set the fee to something higher and with different recipient address and paste on a different txt file with different name.
10. Last step is to broadcast the first 1sat/byte transaction (
the copied Signed RAW transaction hex) to any blockexplorer like
blockstream.info /
blockcypher.com.
After a while, you can broadcast the high-fee transaction and it will replace the low-fee transaction if it wasn't mined yet.
It will be accepted or rejected depending on the node where you have broadcast the first, I've used
blockstream.info for my test.