Unfortunately, this is not possible as such. See this article for information on how to circumvent this problem.
While changing the type of datafield as such is not difficult, consider for a minute the potential ramifications:
- What if you are already using conditional logic that relies on the old datafield type? It obviously won’t work anymore, and leads to data corruption as a result.
- What if you had already assigned values to the old datafield type? Those would have to be deleted first or you would risk data corruption. If that datafield is being used across a variety of different clauses and/or documents, that may lead to a serious impact.
- Questions in Q&A mode rely on the correct datafield type to be assigned to them. If a datafield type needs to change, all the questions this datafield is used in would also have to change.