Let us list down the important points that we need to look at in this discussion -

1. What does the client really want from the project? -

As a project manager you need to go behind the clients statements & find out what he is really looking for from this project. What is his vision for the project? This will throw up some hints on why he wants something to be done in a particular manner or what his idea is behind doing a certain piece of work. Do not hesitate to ask questions or even differ with him on some things.

2. Clarify the scope by involving all -

It is very important for all the stakeholders to sit together & create a proper WBS. By this I mean everybody from the contractor, client, sub-contractor, architects, consultants, & anybody who can influence the project. It does not matter if some are laymen like a local union or an elected representative. They maybe the ones who could come up with unforeseen requirements at some later stage.
It would be a good idea to put up the WBS on a large board on a wall so everybody can see what is being done. There should be a free & fair discussion to come out with all issues without fear or favour.

3. Create a detailed project cost estimate -

Once the scope is agreed & "bought into" develop a detailed estimate for this scope of work. Get everyone involved in this but let the contractor first create it & then throw it open for discussion. The detailed estimate & the discussion builds relationships as everything becomes transparent. Remember this does not change the pricing for the work as already accepted by the parties during award of the work.
The material costs in the estimate also give an idea to the client about the prices of materials & would act as a restraint when he thinks of demanding additional work.

4. Develop & get "buy in" on a formal project execution plan -

This is vital for smooth project progress. The Plan spells out the various Management plans such as Scope Management Plan, Schedule Management Plan & Management plans for Change Management etc. each of which sets out guidelines to define, manage & control that particular area.
The project Plan should also include a Risks Management Plan & Analysis to cater for handling project risks over the life of the project. This too should get the "buy in" of all the stakeholders

Not long back we did a project management competency training for a company in the mining sector who manufactured, supplied & commissioned mining equipment for their clients.. To get them to understand the importance of Scope management we guided them to develop the WBS for one of their projects on a large board put up on the wall of the room. A collaborative interaction brought out all the issues till a "buy in" was reached

Author's Bio: 

Civil Engg. graduate, PMP & Trained Coach, running a project performance improvement training & implementation business since 2011. We help project teams in all industries to pick up skill & knowledge in project management best practices

40+ years in construction projects & project management
Founder-Director (2011-present)

Former Head Projects at Gherzi Eastern Ltd (2007-2010)

Former Asst. General Manager at ITD Cementation India Ltd (1980-2000)

Trained Coach, Erickson Coaching International (2017)

Credential Project Management Professional, Project Management Institute (2010)

Bachelor Of Engineering Graduate in Civil Engineering, National Institute of Technology, Calicut (1976)

Higher Secondary Mathematics, Physics, Chemistry, Central School,Calicut, India (1969)

Lives in Chennai, Tamil Nadu, India (1995-present)