In the mobile app you'll need to use the Adjustment > Temp slider. You may also need to tweak the Hue and/or Tint sliders.

If you don't feel like you can manually make the adjustments like that, you can import the source clips into the desktop editor, make the white calibration and produce the corrected version(s) then use those in teh mobile app.

Depending on how big your clips are and how much of the raw length you're actually using in your produced video, it may be quicker to produce the project in the mobile app and then color-correct the finished clip on your PC.

You can also let CL know that you'd like to see them add a white calibration tool to the app from Settings | FAQ & Send Feedback.