Try Crashing or fast tracking to improvethe schedule. Keep stakeholder updated of the issue and risk to timeline, with details of the mitigation plan, checkpoints to keep them informed on the progress and the issue/risk probability and impact More rigorous monitoring & control, re-emphasize the timelines with the team and keep them motivated with options to catch-up/improve the schedule. Involve team for their ideas, involving team would always make wonders in providing solutions Finally, if you nothing is working, face it and take it up with stakeholders with the risk impact