Those are both very low doses, so I'm guessing you're still figuring out what works. You need to ask the doctor who prescribed it, as they need to know what you are doing.
Speak to your GP or the prescriber. Don’t take any chances if you are pregnant I.e changing doses etc unless you have the right advice.
Slowly decrease dosage and then start on the new medication. I don’t know if you have but speak to your go first though. They may decrease your medication and start you on a low dose of the new one