I am working from an exported data set of Labratory tests, and I need to time from patients arrival to tiem they had a test performed.

The exported file has arrival date and time in one cell, and I use "text to columns" to separate date an time.
The date changes to a standard short date format - great, that what I need
The time is just a "general" format, ie 11:14PM
however I need time to be in military format so I can calculate change in time. so I need 11:14PM to read 23:14, but when I change the formatting of the cell to military time, the cell still reads 11:14PM

Any help greatly appreciated

(I attempted to attach a file, but the website says I do not have permission to perform that task)