Elliott C. answered 10/08/19
Proficient Hebrew Speaker with 8+ Years of Experience
The proper phrase would be "...אם אפשר", as the word "אפשר" is generally used when something is possible or permitted, often used in contrast with the word "אסור", or "forbidden". However, when making a request in Hebrew, it is common to just use the word "אפשר" by itself followed by the infinitive of the action you are requesting, rather than the whole phrase. For example, if I wanted to ask permission to leave a meeting early, I would simply ask: "?אפשר לצאת מוקדם מהפגישה"
Hope that helps!