How would you say 'They book a night (in a hotel)' then? Would you still use reservam or is there another verb specifically for booking accommodation etc? Thanks!
Is it not meant to be in the sense: 'book a night' as in a room for a night in a hotel for example?
Or it also may mean to "keep apart/ set aside".for example, once a week they resevam a night for having dinner together...
"Reservem" is imperative or subjunctive:
Reservem uma noite (For you [plural] and they) — Imperative
Quero que vocês/eles reservem uma noite neste hotel — Subjunctive