After the massive climactic end to the Legion of Doom, Discord knew that his well-intentioned actions had to be rectified in a big way. And since he was directly involved in some of Equestria's most recent events, he already knew who to apologize to first: The Crystal Empire's leaders - Princess Cadance, and Prince Consort Shining Armor.
Even though the couple were already aware of Discord's contributions -- more specifically, how he was the one who revived King Sombra to attack their Empire months prior -- the two were willing to hear him out after he made a formal request for a counsel. Fortunately for them, the remorseful draconequus came prepared with a sincere apology, as well as a couple of thoughtful gifts for the Crystal Empire.
Unfortunately for Shining and Cadance, one of those gifts may have not been nearly as considerate as either of them would've preferred.