It's very difficult to do something like that in a PDF file (unless it was created using LiveCycle Designer).
You'll be better off editing the original file and then creating a new PDF from it.
Thanks for the query.
As of today, Table editing is not supported in Acrobat Pro DC.
As a workaround, if you do not have access to the the original/source file, you can export the PDF file to Word(.docx), perform editing in Word and then create a PDF back from the docx file.
But, this process is not recommended.