Can you transfer money between Clipper cards?

I'm curious to know if it's possible to transfer money between Clipper cards. For those who might not be familiar, Clipper cards are often used for public transportation in various cities. If I have one Clipper card with a balance that I want to move to another Clipper card, is that a viable option? Do I need to go through a specific process or can it be done seamlessly? Additionally, are there any fees associated with transferring funds between Clipper cards? Clarifying these points would be extremely helpful.