how to change type of existing work item attribute
One answer
The UI does not allow to do that. it is officially not supported by RTC. You should create a new attribute with a new type and potentially use CSV export/import to migrate the old data over if needed.
It is possible to modify the process XML to change the type and get away with it in some cases (text), but it is potentially dangerous to do so. E.g. what if the type now means a bigger size (medium text->large text) and what does that mean for the database and the attribute that was already used?
Comments
i created a custom attribute of type contributor, now i want to change it attribute type to medium HTML.
How i can merge data so that the existing work item does not effect. and If some one change the status of work item (close to new) then it should open the work item with new attribute with existing data.
You can export the old existing data to CSV, then modify the CSV by adjusting the value to fit the new attribute, and finally import the CSV back.