My question is how to ask him to call me
"Whenever you're free call me once"
Is this the correct way of telling him to call me? If not, what would be the correct sentence?
My question is how to ask him to call me
"Whenever you're free call me once"
Is this the correct way of telling him to call me? If not, what would be the correct sentence?
You could use either of the sentences bellow (more polite):
Once free, would you please call me?
Would you mind calling me once/when you get a chance?
Call me when you are free (when you get a chance).
The later sounds more like a command but can still be used depending on the context and how comfortable you are with him.