The watch is stuck on military time, and it's really annoying. I lost the instructions years ago, and have no idea how to change it. It is an Armitron WR165 All-Sport watch, and the number on the bottom is 45/6913

https://www.google.com suggests several web sites with suggestions.

http://tv.manualsonline.com/support/armitron/watch/i-cannot-get-my-watch-off-military-time-5752670

Quoting: "David posted an answer 3 years ago
Press the MODE button (B) three times to enter the time setting mode. Press the RESET button (A) to tab through seconds, minutes, hour. The ST/STP button (C) scrolls through the number choices. When selecting the hour, if you want 12hr time format make sure the AM or PM is displayed next to the number you deszire. There are 48 possible selections for the hour - 12 for AM, 12 for PM, and 24 for military time. Keep cycling through until the correct hour comes around. Once you have the correct choice, press the MODE button once more to exit time setting mode."

press adj then mode to change from military to regular

You can get instructions from their web site "Seiko.com".

Click on "support" and then on " instruction booklets" and then scroll down the page and you will see
a list of watches.
Download the PDF for your watch.

advance the hours. The first time you go through the 24 hour cycle, it will be in am pm mode, the second time in 24 hour mode, the next time in am pm. Just keep advancing the hours until it comes up the correct time

When in the time set mode press the A button, this will toggle from military time to standard. I discovered this through trial and error, not in instructions.

Here are the instructions to view, change alarm time and turn off alarm:

From normal time display:
Press MODE once to display stop watch.
Press MODE again to change alarm time.
Press MODE again to change time.

From normal time display:
Press RESET once to display current alarm time.
Press and hold RESET then press START to turn on and off alarm (watch for alarm symbol on top left)
Press and hold RESET then press MODE to turn on daily alarm vs one time (watch day marker lines at the bottom)
Hope this helps.

Maddening, isn't it? Fortunately the solution is here:

http://www.ehow.com/how_5593310_set-athletic-works-watch.html

1 There should be four buttons: mode, reset, start and light. Find the mode button and press it three times until it is in the set time mode.

2 Find the reset button, which usually is located on the bottom right side of the watch face, and hold it until the time starts blinking.

3 Press the start button to change minutes.

4 Press the reset button again to switch to hours.You will know it worked when the hour starts blinking instead of the minutes.

5 Press the start button to change the hour. The watch can handle two modes: standard and military. As you press start, the hour will change from AM to PM, noted by an "A" or a "P" in the top right. When you get through 24 hours, the watch will change to military time and an "H" will be displayed instead of "A" or "P." Keep pressing start to go through another 24-hour cycle and it will revert back to standard time.

With time displayed:

Press lower right, then upper left.

the instructions for getting your watch out of the (military)24hour mode to the 12hour mode are on this page

http://www.grudknows.com/inanemutterings/watch_baby_bgr210.asp

Possibly you can change it back by pushing the hour-setting button through a 24 hour cycle--you can see if you are on military time during the PM part of setting it. If it's on military, just keep pushing till you start over at 12 am again (hint: that's 0:00 in military.) At least, that's how it is on my watch.