We get a lot of questions in my office about expunging records. There is a difference between expunging a person's record and sealing it. In Pennsylvania, if you are convicted of a misdemeanor or a felony crime you are not eligible for an expungement. An expungement destroys an arrest record, it does not take away a conviction.
Sealing a record is much different. In that situation, the records aren't destroyed, we are limiting the ability for most employers to view that record. The only exception is certain government agencies and employers. The process of an expungment or sealing a record are very similar. Both require your defense attorney to file a petition with the court which the prosecution can oppose. If they do oppose your expungement or sealing of your record there is a hearing on the matter.
Remember expunging and sealing are two different situations. You cannot expunge either a felony or misdemeanor conviction in Pennsylvania. Sealing a record is much different, it requires the same process but the result is somewhat different.
So what you need is to talk to your criminal defense lawyer about what you are eligible for and to ask questions.