The right tense for "plans changing"


a customer has asked me to change my plans, the last week we have arranged a meeting for the end of June, but yesterday by mail he has asked to change the date for a new meeting in July 10.

I’d like to reply saying that I agree, I have changed my plans and we will meet the July 10.

But I have a doubt, I already changed my plans and arranged for the new date, what is the suitable tense:

1 - I have changed my plans, we will meet …
2 - I’m changing my plans, we will meet…

Or are they similar in this case?

yes, is that still 10 july.

thank you