I failed TC and opened defect, now defect got fixed and retest defect passed.
what shall i do with result? to add new result or to edit the old one?
If you run the test to ensure that it function correctly now I would create a new result. Generally we do not recommend editing past results, unless its to fix inaccurate information, so that the correct records are preserved for historical purposes. This way the results are accurate in case they need to be discussed for some reason at a later date.
Means when I want to retest specific TC i need to do add result, right?
It may depend on what your team's processes are, but typically each test run will have its own result.
Retrieving data ...