What if the client insists after I explain the constraint?
Treat the second insistence as new information. Ask what the date is tied to, move to voice, and put the trade in writing: If Friday stays, testing drops to one day. If the client still holds the date, accept it with the risk recorded and give the team a checkpoint.
Treat the second insistence as new information. Ask what the date is tied to, move to voice, and put the trade in writing: If Friday stays, testing drops to one day. If the client still holds the date, accept it with the risk recorded and give the team a checkpoint. Repeating the constraint a third time damages the relationship without moving the date.
If the pressure continues past two exchanges, ask for the decision in writing rather than arguing: one line naming the date, the scope you are dropping and who approved it. That converts pressure into a decision with an owner, and it protects the team later, when the trade shows up in the numbers. Keep the tone flat: this is a record request, not a warning.