Your organization has already reduced the notice period to 45 days from 90, so you have to serve a 45-day notice. This is your problem if you cannot serve more than 30 days due to some issue caused by your wrong decision.
In this scenario, the only way out for early relieving is to convince HR to buy out the remaining period or settle the amount due through Full and Final settlement. My suggestion is that you should complete the required notice period if your employer is not willing to consider the buyout option. While there is a legal recourse available, it is time-consuming and not conducive to career growth.