you can remove all transactions from your own mempool by stopping core, deleting the mempool db, and starting your wallet with -zapwallettxes, but that's just from your own mempool. Once a valid transaction has been broadcasted, it'll be stored in the mempool of most of the other nodes of the network, nodes you have no controll over whatsoever.

There is no way of "deleting" a transaction from other node's mempools, the only way it'll get cleared from other node's mempool is if your transaction is included into a valid block, or if the node itself decides to remove the transaction (usually because the mempool is over a certain size, or if the transaction remained unconfirmed for a certain amount of time).