Hi @Carola1 

Good question.

Please reference this help article: https://help.zapier.com/hc/en-us/articles/8496277302157-Change-or-cancel-your-Zapier-plan

Hey @Carola1! It looks like you were able to reach out to our support team who replied with:

Yes, you can choose change your plan at anytime. The good news is that any changes to your Zapier billing plan are done on a pro-rata basis, so you'll only be charged for the days on the plan. Unused time on your plan is applied as a credit towards the new plan you select, which you'll see reflected in the invoice before making the change.

For example, pretend you're on a Starter Plan for $30/month. Halfway through the month, you upgrade to a Professional Plan for $73.50/month.

1. You'll receive a $15 credit (for half a month of Starter Plan)
2. This credit will be applied to the upgrade, so you'll only pay $58.50 for the first month of the Professional Plan
3. One month from the upgrade, you'll pay $73.50 for the 2nd month of the Professional Plan

You can learn more about changing your plan in the article troy passed along from our Help Center: