Step 1: Click on Sent Messages
Step 2: Locate the scheduled message from the records on display (Tip: look for “Pending” under the status box) or to make it faster for you, type the word pending in the search box and select Status, then click on Search. When you do that, all scheduled message will be displayed.
Step 3: Click on Delete (the X icon after read and delivery report icons)
Note: If you need to reschedule the message, click on details, then copy and save the message and numbers so that you can use them to re-schedule the message