help - "Request Feedback Revision" ...

Is there a way to change negative feedback if I've already sent a request to change the feedback and the buyer did not respond.
And now the buyer wants to cancel but can not send him again "Request Feedback Revision"
I agree with the buyer change the feedback but I have no idea how I change it.
Please if anyone can help me I would be happy

call ebay, asap sometimes they will remove it for you

If buyer and seller have come to an agreement then just make the buyer call ebay.
I was once left a negative without the buyer even paying for the item and me shipping it, called ebay and they removed it right away.

You can have the negative changed if you call them depending on what the scenario is.

The buyer is from Germany, I contacted eBay and they tell me that the buyer should request from eBay Germany to change the feedback.
The buyer called and they told him they are changing and not changing,
The funny thing here is that they can see in our messages buyer wants to change the feedback and writes that he spoke with eBay and they told him that change the feedback within 24 hours.
Now the buyer does not respond to me, it attracted too much time,
What can I make friends?

By the way I tried to call several times to eBay Germany but they do not speak in English and it's really unfortunate.