If you are referring to Blurring a Sky in Visual, then it wold not help. IBL, is what getting getting reflected in objects.
So you'd need to Embed IBL into the project first and use Softness control in Adjust Color properties.

Or you can edit IBL image in some external editor without embedding it into the project (they are usually large HDR images)
But make sure to have a copy of an external image before editing in case you'd want to use it in some other project non blurred.

There a couple different types of reflection. We need to know which you mean.

In the visual tab, you can turn on IBL and change the image used by double clicking on it to load a different one. It has a blur option. This is what will reflect on PBR shiny materials.

You can also enable reflection in the material settings. It works in the traditional shader as expected, but if PBR, requires the opacity be set at 99 to work. This a realtime reflection, but only works well on curved surfaces. It also cannot be blurred.

So if you post your visual tab IBL settings and material tab settings, it would help us figure out what's up. Screencaps of both.

Hello 4u2ges, 
hello Rampa,

Thank you very much. That's the solution to my Problem Í´m Looking for a lot of time.
I searched iclone completely but I did not discover this possibility. The blur I can change anytime if it´s necessary. 
A small change in the blur is enough to hide unwanted reflections .e.g. my Video on time 0:38 Here you can see the doll from the HDR background.
To blur the HDR wallpaper itself, which program you can recommend for this. 
That would be a good solution if I need a 100% glossy surface , to hide only the unwanted areas.




many greetings 
GHarry