Beautiful Swap

You are given a tree rooted at node $1$ and each node has a value. You are also given a node $x$ and a value $k$. You can perform atmost $k$ beautiful swap. A swap is beautiful if we choose two nodes $u$ and $v$ such that $u$ belongs to subtree of $x$ (including $x$) and $v$ does not, and one node should be a leaf node and another should be non-leaf node and swap the values of the two nodes. Fin