Ending a phone call when on hold

This may seem like a foolish question, but how do I end a phone call

when I’ve been put on hold? I made a call this morning from my keypad, but the hold time was over 40 minutes. There was only the green phone icon, not the red, so I couldn’t

disconnect. I finally resorted to turning off my phone, but there must be another way to end a call when only that green phone icon is displayed.