Originally named 'Beds' – to change is necessary (5-2)

I believe the answer is:

needs-be

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'necessary' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'originally named beds to change' is the wordplay.
'originally named' becomes 'nee' (I've seen this before).
'to change' is an anagram indicator.
'beds' is an anagram of 'dsbe'.
'nee'+'dsbe'='NEEDS-BE'

'is' is the link.

Can you help me to learn more?

I've seen this clue in The Guardian.

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