nipati …when he falls asleep/sleeps/is sleeping
…if she falls asleep/sleeps/is sleeping

These forms are used for unrealized events, when you want to say that something must happen before something else can happen. It is often found with another verb in the future.

Apu tsheka ut minumatshiut mishta-mitshishuti.
She will not feel good if she eats too much.

These forms can also combine with other preverbs, like the completion preverb tshishi-.

Tshishi-mitshishuti, tshe minumatshiut.
When she has finished eating, then she will feel better.

or a subordinate clause in the future:

Mishta-mitshishuti, tshe minumatshiut.
When he will have eaten enough, he will feel good.

Initial change is not used with this conjugation.

Link to the conjugation guide.