Open Goal Reset

I would like to change the activity goal for Outdoor Walk back to Open Goal. As of now it displays 0.49. I have read multiple forums and the advice is to select the three dots and then choose open. This does not change it back to open it merely starts the activity. I have completed several walks all more than the 0.49 but the goal remains unchanged. I have also read that it tracks your activity and will update the goal; based on historical use of the activities I have found this not to be the case. How do I remove that goal and change back to open?