Convert basically means "to change". It can be used as:
1. To (cause something or someone to) change in form or character: - Could we convert the small bedroom into a second bathroom? - What's the formula for converting pounds into kilograms?
2. To change to a new religion, belief, opinion, etc., or to make someone do something. - He converted to (started believing in) Catholicism when he got married. - I used to hate exercise, but my sister has converted me to it.