The prioritisetransaction RPC accepts the transaction into mined blocks at a higher (or lower) priority
prioritisetransaction "txid" ( dummy ) fee_delta
*bitcoin-cli help prioritisetransaction
prioritisetransaction "txid" ( dummy ) fee_delta Accepts the transaction into mined blocks at a higher (or lower) priority Arguments: 1. txid (string, required) The transaction id. 2. dummy (numeric, optional) API-Compatibility for previous API. Must be zero or null. DEPRECATED. For forward compatibility use named arguments and omit this parameter. 3. fee_delta (numeric, required) The fee value (in satoshis) to add (or subtract, if negative). Note, that this value is not a fee rate. It is a value to modify absolute fee of the TX. The fee is not actually paid, only the algorithm for selecting transactions into a block considers the transaction as it would have paid a higher (or lower) fee. Result: true|false (boolean) Returns true Examples: > bitcoin-cli prioritisetransaction "txid" 0.0 10000 > curl --user myusername --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "prioritisetransaction", "params": ["txid", 0.0, 10000]}' -H 'content-type: text/plain;' http://127.0.0.1:8332/