If you are given a differential equation
$$y'=f(t,y)\qquad\bigl((t,y)\in\Omega\bigr)$$
defined in some domain $\Omega\subset{\mathbb R}^2$, as well as a point $(t_0,y_0)\in\Omega$, you can always look at the solution $t\mapsto \phi(t)$ satisfying $\phi(t_0)=t_0$ not only for $t\geq t_0$, but also for $t\leq t_0$. In other words: The function $\phi$ is also the solution that "terminates" at $(t_0,y_0)$.
In other words: If you are given the closing time $T$ and somehow want to realize $\phi(T)=y_T$ for given $y_T$ then finding the value $y_0$ at time $t_0$ producing the given end value $y_T$ amounts to completely solving the "terminating value problem" described in the first paragraph corresponding to the "terminal data" $(T,y_T)$.