How to Increase Virtual Box Disk size in windows 10

Note: We have to remove ODI 12c Getting Started VM-disk2.vdi attachment (Settings --> Storage) from Virtual Box before following below steps.

I have increased disk size 14g to 20gb in below example:

C:\Program Files\Oracle\VirtualBox>VboxManage.exe modifymedium "C:\Users\rajam\VirtualBox VMs\ODI 12c Getting Started VM - OTN Image\ODI 12c Getting Started VM-disk2.vdi" --resize 20999
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

C:\Program Files\Oracle\VirtualBox>

C:\Users\rajam\VirtualBox VMs\ODI 12c Getting Started VM - OTN Image>dir /s
 Volume in drive C is System
 Volume Serial Number is E28D-8D5E

 Directory of C:\Users\rajam\VirtualBox VMs\ODI 12c Getting Started VM - OTN Image

04/07/2019  08:39 PM    <DIR>          .
04/07/2019  08:39 PM    <DIR>          ..
04/07/2019  08:38 PM    <DIR>          Logs
04/07/2019  08:39 PM             6,278 ODI 12c Getting Started VM - OTN Image.vbox
04/07/2019  08:39 PM             6,280 ODI 12c Getting Started VM - OTN Image.vbox-prev
04/07/2019  08:39 PM    10,615,783,424 ODI 12c Getting Started VM-disk1.vdi
04/07/2019  08:41 PM    15,268,315,136 ODI 12c Getting Started VM-disk2.vdi
               4 File(s) 25,884,111,118 bytes

 Directory of C:\Users\rajam\VirtualBox VMs\ODI 12c Getting Started VM - OTN Image\Logs

04/07/2019  08:38 PM    <DIR>          .
04/07/2019  08:38 PM    <DIR>          ..
04/07/2019  08:39 PM           135,482 VBox.log
04/07/2019  11:17 AM           161,939 VBox.log.1
04/07/2019  08:39 PM           353,519 VBoxHardening.log
               3 File(s)        650,940 bytes

     Total Files Listed:
               7 File(s) 25,884,762,058 bytes
               5 Dir(s)  26,158,559,232 bytes free

C:\Users\rajam\VirtualBox VMs\ODI 12c Getting Started VM - OTN Image>