301 / iTunes / Soundcloud

I want to move my podcast from its current feed URL to my podcast account on Soundcloud.

I have asked the question below to both iTunes support and Soundcloud support but have so far not got a solution.

I am trying to understand the Apple iTunes instructions here re changing a feed url without losing current subscribers:
https://www.apple.com/uk/itunes/podcasts/specs.html#changing
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If possible, you should do two things:
1) You should use the <itunes:new-feed-url> tag...
2) You should set your web server to return an HTTP 301 response and redirect
when receiving a request for the old feed.
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So the instructions seem to say add a <itunes:new-feed-url> tag to the old url and also put a 301 redirect on the old URL.

In its normal meaning, a 301 redirect means that any content on the old url (such as the <itunes:new-feed-url> tag) would be ignored.

So how can the <itunes:new-feed-url> tag on the old feed URL be effective when there is a 301 redirect on the same URL?

Thanks...