Where do you want to show the day-and-time? If it will be in the axis, Tableau is going to create the axis increments to include time.
Consider using DATEPART to extract the day and hour and minute and seconds (if needed) and create a string label that spells out the specific value, and put that on your mark label or in your tooltip.
There is also a DATENAME function if you want to get "Tuesday" instead of 9 as your value for the day.
Here is a link to all the date functions. I can never remember them off the top of my head, so I go here to get the function I want and the syntax.
Hi Samyak, have you tried manually changing the end time default date format to dd hh:mm:ss?
Otherwise, something along the lines of
STR(DAY([end time]))+" "+STR(DATEPART('hour', [end time]))+":"+STR(DATEPART('minute', [end time]))+":"+STR(DATEPART('second', [end time]))
This will give you a string, which may not be what you want, but these are the two options that immediately come to my mind.