A stuck opener that flashes and reverses is usually a sensor problem, and it's fair game to check yourself before you call anyone. Wipe both sensor lenses, make sure nothing is blocking the beam between them, and look at whether the brackets have been bumped - a stroller, a bike, a snowblower backing out. If the lights on both eyes go solid instead of blinking, the door should close.
What you should not touch: torsion springs, cables, or anything under load. That holds everywhere, but it matters here because a good chunk of Bartlett's 1992-era stock still runs original springs closing in on their rated cycle count, and a spring at the end of its life doesn't give much warning before it lets go. If the door is off its track or a spring has already snapped, close the area off and call - don't try to force the door up or down by hand.