Well, you can initiate the transaction with same input referenced, but the node in the network will not add your transaction in their mempool, since they already have an transaction with same input.
Any transaction can stay in mempool upto 14 days, after that it gets invalidated and rejected. So you have wait 14 days
Some things you need to remember about bitcoin:
Bitcoin is cash, not a bank account. These are very different models.
You pay by handing over digital coins, not by making a bank-transfer between accounts.
No one but you cares what total amount of Bitcoin money you have, they don't need to know.
This fundamental misunderstanding comes up a lot in different ...
The tweet seems very confused. Most likely, they meant "60% of the hashrate" rather than supply. It's not clear from the tweet what they mean with "verify a fake transaction". Charitably, one might interpret that they could execute a Finney attack, or execute a doublespend attack by reorganizing the chaintip in a form of majority attack. ...