The moment you select a rate, the pricing is fetched live from Mews and shown in the Room Block grid. Once a Room Block is synced with Mews you cannot change to a different rate.
You can change the pricing, but if you selected the wrong rate and clicked save, you’ll need to mark the group as “Lost” to delete it in Mews, then delete the group in ET, and start fresh.
Update Rates on the Group manually:
Select the Details Sub-tab in the Booking
Select Edit on the Room Block
Select Add/Edit Room Rates
Modify the Rates
Optional - Click Rate Override to change specific dates, instead of the whole block.
Repeat step 4 for any other Room Types
Click Okay
Save the Room Block