If you believe a schedule required by the client is unreasonable, you should document your reasons for believing so, and inform the client of those concerns in writing.
If the client still chooses to go ahead with a schedule that you are not a party to (for example for their construction contractor) but using your company’s designs, you should inform them (with details) of your concern in writing.
This may reduce the possibility of claims and your liability in the event of contractor over runs.
If you believe a contractor’s schedule is unreasonable, you should also inform the client in writing.