Used a variety of methods, as one knowing the ropes? (4,3,7)

'used a variety of methods' is the definition.
(ring the changes means do in different ways)

'one knowing the ropes?' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'the' (both can introduce a definite example of something) and 'the' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

'as' is the link.