Hey there balajivs39,
Thanks for reaching out to the Apple Support Communities.
If wanting to prevent Siri from announcing Reminders on your Apple Watch, you can disable this by going into Settings > Notifications > Announce Notifications, and from there disable Reminders. You can also say something like "Stop" or "Cancel" to have Siri stop reading the notification.
For more details, check out this link here: Listen and respond to notifications with AirPods and Beats headphones on Apple Watch - Apple Support
Stop Siri from reading a notification
You can do any of the following:
* Say something like “Stop” or “Cancel.”
* Press the Digital Crown (AirPods Max).
* Note: While listening to a notification, you can turn the Digital Crown to change the volume.
* Press either Force Sensor (AirPods Pro and AirPods 3rd generation).
* Double-tap either of your AirPods (2nd generation).
* Remove one of your AirPods (AirPods Pro and AirPods 2nd and 3rd generation).
If you didn’t turn on Announce Notifications when you set up your AirPods, open the Settings app on your Apple Watch, go to Siri > Announce Notifications, then turn on Announce Notifications.
We hope that's able to help.
Have a great day!