There are two main types of merge freeze: a manual freeze and a recurring freeze.
To implement a manual freeze all you need to do is click the big red “Freeze” button inside your protected branch in the Merge Freeze control panel. This will update the Merge Freeze status in Github to a FAILED state. Depending on how you’ve set up your protected branch in Github this will either block merging completely or be a visual indicator that merging should be avoided.
Sometimes you may want to get one pull request merged and deployed while still blocking other pull requests from being merged.
You can achieve this by clicking the “Unfreeze 1 pull request” button. A prompt will appear asking you to enter the number of the pull request that you would like to unblock. This is the number found in Github that sits alongside the title of the pull request. It also appears in the URL of the pull request like so: https://github.com/My-Company/My-App/pull/5.
Enter this number into the prompt, submit and Merge Freeze will update the status of that PR so that you can merge it into your protected branch.
Unfreezing single pull requests are only available if your project's freeze method is "Push a status update to all PRs".