Many of us are facing this issue with ‘Pending cancel’ status of orders which prevents any further action on the position. If you want to know how prevalent this issue is, just search for ‘pending cancel’ on the forum and you will see many frustrated posts!
It is a major bug that prevents trading (automated via API or web interface).
It makes for a very unreliable trading platform. Hope someone in dev team takes a look at this and puts a high priority on this issue. At the minimum, tell us how to clear this pending cancel state and actually cancel the order.
I have tweeted @AlpacaHQ about this issue. Here is the link to my tweet.