I just realized that the datatype of the `PK` column of my data extension should be of type *Text* instead of *Number* (otherwise I can not link it to the `ContactId`).

The data extension is rather big with about one hundred columns and already populated. I tried duplicating it to be able to remove the PK column and then re-uploading the data into it. But the column does not seem to go away simply by manually deleting it.

How can I change the type of the PK column without manually recreating the data extension?