API v2 - Deleting value

Hi

When using API v2 “Updates a row in a Big Table (PATCH)” - Docs
I cant clear value.

Have tried setting value to “”

{
  "xxxx1": "Alex Bard",
  "xxxx2": ""
}

But old existing value persists in table.

Have tried running the same API “setup/configuration” multible times, where i set the value of “xxxx2”: “x” or “xxxx2”: “1” that works. So its only when i use “” it fails to update.