Deadass
The social cheat I’ve learned for this is to say:
“I have to check my calendar, why, what’s Friday?”
This says “Maybe” without saying “Maybe”, and giving you the option to make up a Doctor’s Appointment You Forgot About (or reschedule one you didn’t!) depending on what they say.
It’s an amazingly powerful sentence for my Autistic and ADHD ass - it gives me the ability to judge my social spoons, as well as communicating that “hey, I might have forgotten something, it’s not you it’s me” in a very non-offensive way.
“I have to check my calendar, why?”
I actually never know what’s on my calendar, so it’s not even a lie when I say this!