Delete a field from a class

Hi, I am using class editor to change the property (type from Date to text area) of a class field (say field A). For that first I created a new filed (B) with the desired type. Then I changed the number of the old field, A to the one next to the last one existing. (say we have 20 fields now with the new one B. So, I assigned A (originally having number 14, a new number 21). I then assigned B number 14 to replace A. I am having problem next when I am trying to delete A so that I can then rename B to A. I tried to change number of A from 21 to 0, also deleting name of A so that it has name property to be empty. But nothing helps to remove A from the picture. Some how all the fields from number 1 to 14 gets deleted! Does anyone have any idea on that? Thanks Sohana