Accounting for business vehicle

[AJ D.]

My Rental PIS date will be August 1, 2024. I currently just have a 2-door honda that I will use for business travel/managing the rental. Ideally, I'd like to buy a more practical car for managing my rental (something with more storag space) later this year. 

Question - Can I use standard mileage for my current honda, and then once I buy a business vehicle use actual expenses? Or, do I have to stick with 1 (standard or actual) for the whole year, regardless of a new car purchase?