Make new confession to let in again (7)

I believe the answer is:

readmit

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'let in again' is the definition.
('admit' can be a synonym for 'let in' so perhaps 'readmit' is OK for 'let in again')

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for readmit that I've seen before include "Welcome back" , "Dear Tim (anag.)" , "Again accept" , "Let in a second time" , "Allow back into" .)

I've seen this clue in the Sydney Morning Herald.

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