Yes, there are two ways for a state to be removed from the MSIGA. The first is that a state can voluntarily leave the Agreement as long as it provides at least 60 days' written notice. Secondly, a state can be expelled if 75% or more of the members so vote (excluding the representative of the state in question who is expected to recuse himself or herself from any such vote).
No state has yet joined the MSIGA and then left, so these provisions of the MSIGA have proven moot so far.