If your client asks you to make use of a ladder and you are not comfortable with this, politely let them know and explain why (e.g. “I am not comfortable climbing a ladder in your home because it is a safety risk. I could fall and hurt myself”).
Always try to reach an agreement with your client (e.g. “Can I use a broom or a mop to reach the high places?”).
If anything happens/goes wrong, the client will be responsible to pay for any doctors/hospital bills - it is best to not put yourself in a position that could be dangerous. You can also reach out to your support team when you are at the booking if you need help in explaining this to your client.