We’ve added Mercenary Mode to the 6.2.1 PTR, and we need your help testing it out. When we activate it on Wednesday, August 5, you’ll be able to head to any unrated Battleground or Ashran to test Mercenary Mode. Here is the information we posted on July 15:
Players will be able to act as a mercenary for the opposite faction in PvP whenever your faction is experiencing a long wait time to get into Ashran or unrated Battlegrounds. Agents of the enemy faction will appear in your base in Ashran (Stormshield for the Alliance, Warspear for the Horde) and allow you to enter Ashran or Battlegrounds disguised as an enemy player, and actually fight as the opposite faction. While competing as a mercenary, players will automatically have their race changed into one appropriate for the opposite faction. Players will still be able to earn all the same rewards as winning or losing as their original faction (with the exception of faction-specific achievements).