Converting Time When Formatting Doesn't Work

[ocgk1513]

I am exporting data from a software program that uses general time (12 hour) into a sheet that has a formula that will only work with military time(24 hour). When I attempt to change the time format to 13:30:55 it does not work and remains at the 12 hour format it was imported at. Is there another way to change to military time that does not include the Format Cells option?

 

[awoohaw]

Is the file that is exported out formatted as HH:MM AM/PM, or just HH:MM? If the later how do you know it is a PM time and not an AM time?
A sample of the raw data would be extremely helpful.