I don't want to see comments on my slides, but I don't want to delete them, either.
If you don't want to delete your comments, you can hide them so they don't appear on a slide. To do so, click the Markup button on the Reviewing toolbar to toggle off the comments. Comments will never appear in an actual slideshow.
The button I need doesn't appear on the Reviewing toolbar.
Many of the buttons on the Reviewing toolbar appear as a result of an action in the review process. For example, you might need to open a presentation for review to activate some buttons or merge presentations to view others. If you can't find the button you want, be sure you've completed the prerequisite steps to get where you want to be in the review process.