@Daniela1679
Changing prices in the listing works well for me.
There are several ways to do this, you did not mention which method you used.
If you do not want tot use Smart Pricing at all , simply turn it off and set fixed nightly price.
If you only want fixed prices for certain dates: select the dates on the calender, switch Smart Pricing off (for that dates) and set the fixed price. Do not forget to Save !
Changes will be immediatally shown in the calender and on the listing.
Best regards,
Emiel