Translation:The actress changes in the bedroom.
It's perfectly acceptable in English to just say that the actress "is changing" - if you don't specify what someone is changing, it's assumed to be their clothes.
Unless you mean that, say, the person's character is changing or they're getting taller or something. But that's not usually something that happens only in a bedroom.
Thanks for that.
Also, we probably should not try a literal translation of "átöltözni", right? "Cross-dressing" means something else in English.