To answer your question unfortunately there is no way for you to change your current Feedlink URL since each Feedlink URL is claimed by a specific person and is unique to them.
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Once a Feedlink URL is created, it becomes permanently associated with the user who claimed it until it's not made available again by that same person.
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If you desire a new Feedlink URL, the process involves creating a new one altogether. You can check if your desired Feedlink URL is available on this link and, if it is, you can claim it right away.
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However, please note that this will be a completely new Feedlink, separate from the current one that you have.
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