More often than not, this transitional coat change will also bring about color changes. Some owners are disappointed to hear this if they are in love with the color of their Pom's coat. However, a lot of things can happen:
Colors can darken - Tans may turn brown, oranges may deepen to red, etc.
Colors can lighten - The opposite can occur with browns lightening to tans, reds fading to orange, or oranges fading to cream.
Markings can change - Patches can decrease or increase in size. Brindling can lighten or darken.
This said, there cannot be a change such as white turning to orange or black changing over to cream.
At the end of the puppy uglies, your Pomeranian will be the color that he genetically is meant to be.