it seems to be impossible.
I recommend to use a column of type string and copy the time values (Column 1 of my example) to the string values (Column 2):
var t:time := TableFile[1,j]
t := round(t)
var str:string := to_str(t)
TableFile[2,j] := copy(str,1,strLen(str)-5)
For instance 3:45.9000 will be "3:46".
Thank you Peter,
It works. I just wanted to show the result exporting to Excel. This way the excel shows the same format as the plant format whitout any issue.
PS: I do not need precision at my report. So it's ok hidding the 5 last elements.