AutoCAD MEP-HVAC : can't modify the diameter of duct

[alexandro.b]

I have a problem , while I was drawing I wanted to change duct diameter and I could't because MEP didn't let me modify , for some reason . Until then , I was able to modify duct size . If I start to draw a new duct and go to properties they let me modify , but to old duct then don't.

[andkal]

Check if the dimmensions are not locked accidentally.