I'm new to Python and regular expression. All the examples I've found online appear to be very ambiguous and vague.
For example, in these few entries.

```
     2016-01-15T11:40:00-08:00 Valedictorian candidates meet for instructions
     2016-02-26T15:05:00-08:00 Valedictorian written submissions due
     2016-03-17 St. Patrick's Day
     2016-03-25 Good Friday
     2016-03-27 Easter Sunday

```

I want the end result to be similar to the last 3 entries. (Removing the time, noted by TXX:XX:XX-XX:XX)
while also preserving the summary.
If anyone could tell me how to program this in a simple way in python or give me some pointers, it would be much appreciated.

Edit:
The data is being stored in a simple .txt file that was outputted through python as well, as the python program grabs values from Google Calendars in above output. But I want to have the regex within it as well to remove the time format. 
Also. Google doesn't allow removing the time/putting it in another timedate format, as far as I know.

Edit2:
**All entries are in output.txt**

Thanks in advance.