Need to add time to multiple cells containing date AND time of previously created spreadsheet

[KristaRN]

Hello,
I am Using Windows 7 and Excel 7, I have a previously created spreadsheet in which cell B2 contains the date AND time. It looks like this: 2015-07-17 12:55. There is no formula in the formula bar, and it is in a "general format" as best I can tell. (I did not create this spreadsheet.) The spreadsheet is populated from an upload from a piece of medical equipment. Unfortunately the time was off on the equipment by 47 minutes and I need to add that time back in to all of these cells (B2-B5621). Is this possible? This is a minute by minute spreadsheet for 72 hours of data.
Thanks!

 

[KristaRN]

AlanY and gebobs,
Thank you both for your help. I basically used both of your suggestions, entered the corrected dates and times in two new columns and added in the 47 minutes. It seems to have worked!
Krista