I need a quick reality check. I'm a first-time manager and sometimes have difficulties judging whether my expectations towards my subordinates are realistic or not.

How assertive/ cooperative should I be in the following situation:

You work on a project with your subordinate, discuss it thoroughly. Then you meet a client (one you know very well but still, it's a client) and present the results together. After you presented a proposal, your colleague tells the client he doesn't agree that the proposal you just presented is the best one and goes on to discuss a different one.

Now, my first reaction is to have a quite serious conversation with the colleague asserting that this behavior is unacceptable. Are there any better options? If the best solution is to discuss it, how should I frame it?

Btw, it's not the first time this happened.

I'm a first-time manager and sometimes have difficulties judging whether my expectations towards my subordinates are realistic or not.

How assertive/ cooperative should I be in the following situation:

You work on a project with your subordinate, discuss it thoroughly. Then you meet a client (one you know very well but still, it's a client) and present the results together. After you presented a proposal, your colleague tells the client he doesn't agree that the proposal you just presented is the best one and goes on to discuss a different one.

Now, my first reaction is to have a quite serious conversation with the colleague asserting that this behavior is unacceptable. Are there any better options? If the best solution is to discuss it, how should I frame it?

Btw, it's not the first time this happened.

I need a quick reality check. I'm a first-time manager and sometimes have difficulties judging whether my expectations towards my subordinates are realistic or not.

How assertive/ cooperative should I be in the following situation:

You work on a project with your subordinate, discuss it thoroughly. Then you meet a client (one you know very well but still, it's a client) and present the results together. After you presented a proposal, your colleague tells the client he doesn't agree that the proposal you just presented is the best one and goes on to discuss a different one.

Now, my first reaction is to have a quite serious conversation with the colleague asserting that this behavior is unacceptable. Are there any better options? If the best solution is to discuss it, how should I frame it?

I need a quick reality check. I'm a first-time manager and sometimes have difficulties judging whether my expectations towards my subordinates are realistic or not.

How assertive/ cooperative should I be in the following situation:

You work on a project with your subordinate, discuss it thoroughly. Then you meet a client (one you know very well but still, it's a client) and present the results together. After you presented a proposal, your colleague tells the client he doesn't agree that the proposal you just presented is the best one and goes on to discuss a different one.

Now, my first reaction is to have a quite serious conversation with the colleague asserting that this behavior is unacceptable. Are there any better options? If the best solution is to discuss it, how should I frame it?

Btw, it's not the first time this happened.