"Venture capital firms holding positions in OpenAI’s for-profit entity have discussed working with Microsoft and senior employees at the company to bring back Altman"

"The playbook, a source told Forbes would be straightforward: make OpenAI’s new management, under acting CEO Mira Murati and the remaining board, accept that their situation was untenable through a combination of mass revolt by senior researchers, withheld cloud computing credits from Microsoft, and a potential lawsuit from investors"

This is not saying that Microsoft has threatened to withhold the compute credits. It is saying that VC firms are hoping to use that as a strategy for force their hand. Microsoft may or may not agree to this.