This came up today - while pulling my phone out of my bag when the alarm went off, I accidentally touched "Snooze".
I didn't want to have it snoozed, I wanted it dismissed entirely - but I couldn't work out how to do this. When I swiped down from the top to look at the snoozed alarm, it just took me to the alarms page.
This is a daily alarm that repeats every day of the week, so I couldn't just turn it off. I guess you could say I wanted to dismiss the snoozed instance of the alarm, not the alarm itself.
On my last phone (Sony Xperia), when you swiped down from the top to look at the snoozed alarm, there was an option "Dismiss". Can I / how can I have the same functionality on my new Samsung S9?
Edited to add tags.
This was posted a while back, so you have probably figured out the solution.
Anyway, you must go to SETTINGS, then NOTIFICATIONS, and the choose CLOCK.
Once you turn on notifications, you will see several choices, with switches that turn each off and on.
There is a switch that will show the active alarm on the notifications screen. Once you have activated that switch, you can pull down the notifications screen and dissmiss the already snoozed alarm from there.
It too me ahwile to find this, but I'm glad that I did 🙂