Deleting a header in Excel is a relatively simple process, but there are a few things you need to keep in mind. First, make sure that the header is actually selected. If it's not, you can click on the header to select it. Once it's selected, you can press the Delete key on your keyboard to delete it.
If you accidentally delete a header, don't worry! You can always undo the deletion by pressing Ctrl+Z on your keyboard. This will undo the last action you took, which in this case would be deleting the header.
Once you've deleted the header, you'll need to insert a new one. To do this, click on the Insert tab and then click on Header & Footer. This will open up the Header & Footer editor where you can insert a new header. Simply type in the text you want for your header and then click on the Insert button.
That's all there is to it! Deleting and inserting headers in Excel is a pretty straightforward process.