Verb
To make softer.
(by extension, idiomatic) To appease someone in order to make them more receptive to an idea or proposal.
To become less committed to something.
Source: en.wiktionary.orgAnd, I’m really hoping that the rains will set in so that soil will soften up enough that I can dig up some of the new garden beds at least enough so that I can get the garlic planted and some new tulip bulbs tucked in. Source: Internet
That’s to soften up the fibres. Source: Internet