You could also use Azure Traffic Manager to route the traffic based on a set of rules, such as geographic location, to minimize the impact of the swap. Note that this method allows you to reduce the downtime by gradually redirecting the traffic to the new version of the app, but there still may be some downtime during the process of swapping the slots.

Remove the old slot: Once the new version is stable and all traffic is being served by it, you can remove the old slot.

Switch the production slot: When you are ready, switch the production slot to the new version of your application by swapping the slots.

Monitor traffic: Monitor the traffic split between the production and staging slots to ensure that it is working as expected.

Start traffic routing: In the Azure portal, navigate to your App Service, and under 'Deployment slots' click on 'Traffic routing' and configure the traffic split between the production and staging slots.

Test the new version: Test the new version of your application in the staging slot to ensure that it is working as expected.

Deploy new version to the staging slot: Deploy the new version of your application to the staging slot.

Create a new deployment slot: In the Azure portal, navigate to your App Service, and under 'Deployment slots' click on '+Add slot' to create a new deployment slot.

Here are the general steps to switch deployment slots in Azure App Service without any downtime:

This is done by creating two deployment slots for your application, one for the old version (referred to as the 'production' slot) and one for the new version (referred to as the 'staging' slot). Switching deployment slots in Azure App Service without any downtime can be achieved using a feature called 'Traffic Routing' or 'Traffic Manager' which allows you to split traffic between the old and new version of your application.

Azure web apps deployment slots swap