2 answers
@Stefanie : It clearly states that the text area field you are trying to change is referenced in the Flows . So first you have to DEACTIVATE them and then change the datatype , Then you have to Activate the Flow .
Follow below steps to ACTIVATE / DEACTIVATE a flow :- From Setup, enter Flows in the Quick Find box, then select Flows.
- Click the name of the flow.
- Click Activate or Deactivate next to the relevant version of the flow.
P.S : When you activate a new version of a flow, the previously activated version (if one exists) is automatically deactivated. Any running flow interview continues to run using the version with which it was initiated.