If you fail to renew the policy on time, it will expire, you will cease to have health coverage and the cumulative bonus and the waiting periods from your previous policy will also lapse. But, there are some things you can do:
Revive Your Lapsed Policy
Some insurance companies will allow you to revive the lapsed policy by paying the outstanding premium amount, with added interest. In this case, you might have to undergo a number of health check-ups to clarify the state of your health before the insurer reinstates your policy.
Buy a New Policy
In many cases, you cannot renew your old policy, and you must buy an entirely new policy, either from the same insurer or a different company. This policy will not include any continuity benefits like bonuses, and you will have to complete all the required waiting periods for pre-existing diseases, maternity benefits, etc. again from the start.
Additionally, since your premium will be calculated from scratch, it will be higher. This is because of the lapsed policy, and the fact that you will be older than when you bought the previous policy.