Yes. You'll be eligible for Pakej MyKabel after serving 6 months of your contract.
Just log into selfcare and you should see a pop-up offering the Pakej MyKabel promo.
However, your contract will be reset to 24 months. Discount will be given in your upcoming bill.
If you've completed your 24-month contract, you can switch to Pakej MyKabel anytime and sign a new 24-month contract.