Pattern application

[client_4]

Hi there,
I'd need to apply a pettern as a wallpaper in a photo.
I know the steps to apply a pattern when the background is white, but this time, the photo has its own wallpaper, I have to replace it, but I don't know how to do it.

Thank you!

[Nancy OShea]

Does the image have editable layers or is it flattened to a single layer?

On a flattened image, removal of wallpaper could be tricky to impossible. 

Can we see the image you're working with please?

[client_4]

Here it is the Image! 
I'd like to replace the wallpaper, but I need to "delete" the one this one firstly.
I've tried to select the coloured areas and tried to subsitute the lights of the colours with the colours of the wall, but i failed 🙂
I would like to avoid the use of clone stamp or similar because I would need much time and I am not sure if it's the right method to have a good result

Thanks to those who will help

[Kenneth Kawamoto]

Looking at the image, I think you can mask the wall with Vector Mask (or Layer Mask)

[client_4]

yes, that could be the fastest option but then I would not have the light of the environment 

[Kenneth Kawamoto]

I would paint shadows on a layer between the (masked) foreground and the new wallpaper layers.

[Semaphoric]

I would select everything that is not wallpaper, probably with Select Subject, and make that a layer mask. You would then put your new wallpaper on a layer below that, and an additional layer between them for painting the shadows in.

[client_4]

That could be a good option too, but how can I recreate the light of the environment that is on the wallpaper that I had?

[Semaphoric]

That's what the middle layer would be for. You would paint in the lighting and shadow with a large soft Brush in airbrush mode. Set the brush to low opacity and flow, and build it up slowly.

[Nancy OShea]

Challenge 1:  The camera angle is not perfectly perpendicular to the wall.

Challenge 2: Flesh tones and clothing colors are too similar to wall color which makes it very difficult to separate background from foreground elements.

Challenge 3: Uneven lighting.

I don't think this is a suitable photo for a natural looking background replacement.  My fear is that you could spend several tedious hours on this and it will still look  "Photoshoped."

Do you have any other images to work with?

[client_4]

Thanks for all the answers, I will try many other attemps or I will change the photo.
Thanks again for you time!