You must be at least level 70, already be in [[w:c:wow:#|Dalaran]], and do the [[w:c:wow:#|Learning to Leave and Return: the Magical Way]] quest (from [[w:c:wow:#|Archmage Celindra]] across from [[w:c:wow:#|Krasus' Landing]]) to access the [[w:c:wow:#|Teleport to Violet Stand Crystal]] and [[w:c:wow:#|Teleport to Dalaran Crystal]].