How can I customize the Subscription Date of Membership 2 pro?

Hello!
I am integrating Membership 2 into my company website, so that our existing members can make payments. However, each of our members already has a different date from which they make their annual payments.
How can change and customize the Subscription Date of a member?
Additionally, is their any way I can add automatic late fees?

You help is much appreciated,
Thank you