You don't necessarily need to disassemble and return it in the box. I bought and returned two bedside tables (HEMNES) recently. I only constructed the first and was unhappy with how it looked once it was in my room. They accepted the returns no questions asked.
Has that changed? I know several who have complained about needing to return it in its original packaging. At least I'm pretty sure it was IKEA that they conplained about - and there have been several.
I'll defer to you, as I haven't actually even been in one, personally.
