Starting from Octez v12.0, a replace by fees feature will be available on the Octez shell implementation:
This will enable the user to replace a manager operation in the Octez prevalidator's mempool (valid or not), for another manager operation - which either has more declared fees, or a greater fee/gas ...
You can use the RPC to ban/remove an operation (The endpoint should be protected with an ACL for safety reasons).
The RPC endpoint is POST /chains/main/mempool/ban_operation (This link includes the endpoint specification).
The operation is removed from the mempool, and its effect ...
You need to configure your nodes with --rpc-addr 0.0.0.0:8732 --allow-all-rpc 0.0.0.0:8732 parameters or modify your config to allow remote access by adding 0.0.0.0 to rpc.listen-addrs :