I heard this directly from R' Laibel Groner.
The Lubavitcher Rebbe once got a fax from a woman that was in an accident/shooting (Don't recall). Her whole face was messed up and the doctors said she'll need 4 surgeries done on her face. R' Groner brought the fax to the rebbe. The Rebbe said that even though I wasn't planning on going to the shver (his FIL's kever) tommorrow (certain times he didn't generally go) We'll go anyways to daven for her.
The next day they went to to the kever, upon leaving, the rebbe asked r' groner to call the doctor for an update. R' Groner called and the doctor informed him that it looks now that she'll only be needing 3 surgeries. R' Groner repeated that to the rebbe. The rebbe responded tha't we'll have to go again tommorrow. The next day they went, R' groner called the doc. the doc informed that it now looks as if she'll only need 2 surgeries. The rebbe told R' Groner "we'll have to go again tommorrow. ..... till she didn't need any surgeries!