Consider the problem \begin{align} \min\limits_{x\in \mathbb{R}^n} J(x) \quad \text{s.t.} \quad e(x)=0, \ g(x)\leq0. \end{align} Reformulate this problem into a problem with equality- and box constraints.
By box constraints there are just simple bounds meant, i.e. \begin{align} x\in \{x\in \mathbb{R}^n: x_a\leq x\leq x_b \ \text{componentwise in } \mathbb{R}^n\}. \end{align}
You could add a slack variable $s$ and write
$$ \min_{x,s} J(x) \quad \text{s.t.} \quad e(x) = 0,\; g(x) + s = 0 $$
with the box constraint $s \geq 0$.