I have added my parents in HIS this year. Does anyone know how many days I need to wait I need a knee replacement surgery for my father.

90 day's

I don't think there is any waiting period, but confirm with the team

Drop a mail to corporate.his, they will guide you.

In general everything starts from the day policy is issued but if you have declared any pre existing illness then there will be waiting period. Whatever the case is either you can call HIS or email them. Here HR can't help as you will only get general idea.

Also you can check the health insurance policy details in Knommax my policy hub

Call the HIS number and confirm with them. Insurance company has waiting period for some existing illness. You need to confirm if you have a waiting period.