Can I swap my bed for a different one?
cam-BIA-re — three syllables, stress on the second.
Ask at reception if you were assigned a top bunk and prefer the bottom, or if your dormitory is noisier than expected.
'Posso cambiare' = can I change. 'Con uno diverso' = for a different one. 'Uno diverso' refers back to 'letto' (masculine). Bed swaps depend on availability — hostels will accommodate reasonable requests when possible.
Preferirei un letto sotto.
I would prefer a bottom bunk.
State your preference directly
Posso spostarmi in un altro dormitorio?
Can I move to another dormitory?
Ask if the current dormitory has persistent noise or temperature problems
C'è qualcuno che vuole scambiare il letto?
Is there someone who wants to swap beds?
Sometimes other guests will voluntarily swap
Top bunk phobia is extremely common among hostel guests. Italian hostel staff are very accustomed to this request and will accommodate it whenever possible. If you specifically need a bottom bunk for medical or comfort reasons, mention it at booking — many platforms allow you to request one.