Select any cell in the sorted range
Go to the Data tab
Click Sort
In the Sort dialog box, click Delete Level or clear the sort criteria
Click OK
To remove only the sort order visually, re-sort the data by the original column or desired order
To restore the original order, use Undo immediately after sorting
If the data is in a table, use the filter drop-down and choose Sort A to Z or Sort Z to A only if you want to change the sort again
If needed, convert the table to a range to manage sorting manually