how to get old blanchy shadowlands

Assuming you are referring to the Blanchy’s Shadowlands mount:

Blanchy is a wild basilisk that roams the Verdant Wilds in Revendreth. Players can tame Blanchy by first weakening it with chain fighting, then feeding it a Bloodberry.

Once tamed, Blanchy can be used as a mount to travel around Revendreth. To get to the Verdant Wilds, players need to take the path that leads from the Court of Harvesters to the north.

Blanchy is a wild creature and can be difficult to control. If a player dismounts in an area where Blanchy is not comfortable, it will become agitated and may attack. Players need to be careful when taming Blanchy and should be prepared for a fight.