Open to command prompt in windows
Go to the directory where "adb.exe" is located as follows.
cd C:\Program Files (x86)\Android\android-sdk\platform-tools
then type "adb shell"
Then you would see something like this
shell@grandpplte
$
That means you have successfully load the android debugging bridge.
If you get an error, most probably you might not have given access for USB debugging in your android phone. So go to developer options in your android phone and turn it on.
If you have got "shell@grandpplte
$" type below commands without missing a single letter.
Type - sm list-disks
Then you'll get somethng like "disk:179,128"
It is your disk name (You will get something different than this ex:- "disk:xxx,xxx")
Type - set-force-adoptable true
Type - sm partition disk:179,128 mixed 50
(In here if you want to make your sd card into a 100% internal memory, you must type "private" instead of "mixed 50". As well as "mixed 50" means partition size in a ratio.
You also can chage it as you wish.)
Type - sm set-force-adoptable false
Type - Reboot
Once yor device rebooted, go to the storage setings and slect migrate data.
Now you are done.
Thank you