from Eric Macramalla, TSN Legal Analyst,

While decertification is the players walking away from the Union, a disclaimer of interest is the Union walking away from the players. So a disclaimer of interest occurs when the Union terminates its right to represent the players. It's also a less formal process than decertification. It can be as quick as Donald Fehr sending a letter to the Commissioner's office declaring the NHLPA no longer represents the players as a bargaining agent. There's no vote, no petition and no decertification election.

more on the difference between decertification and disclaimer of interert...

added 1:30pm,