If you make changes on SoundCloud, they will automatically update your RSS feed. From there, it is up to Apple Podcasts to refresh its cache and recognize these changes. It can typically take up to 24 hours for Apple to update your podcast. 

What should I do if changes aren't reflected on Apple Podcasts?

First, make sure that your feed is valid here.

If your feed is NOT valid, then Apple cannot read and show the changes you have made. If your RSS feed is showing error messages, please go to our Help Center article here for more steps on how to make it valid again.

If your feed is valid, then this means that Apple needs to refresh its cache and recognize the changes you have made. As a hosting platform, SoundCloud does not influence how fast Apple Podcasts updates its store. Generally, Apple updates within 24 hours. If you do not see your changes reflected within 24 hours, you will have to reach out to Apple directly.