How can you manage complex projects with uncertainty?

Develop Risk Management Plan and have an open discussion with the stakeholders, technical teams etc to ensure every risk is captured from the beginning of the project till end of the project. Risk assumptions is an important criterion for every project no matter the level of complexity. You need to think 10x ahead for the kind risk that the project team will encountering be it technical,people,process,procurement,timeline etc.One of the most important note stakeholders' engagements to frequently communicate with your customer no matter how complex is the risk and issues that the project team is facing...the key is transparency.