hi ,
i changed my profession from technician to sales representative. for me it was simple with little humps following are the list of documents which u require.
1.Application form
2.NOC from company
3.certificate translated in arabic this can be done in any typing center
4.id copy of the authorized person.
5.old agreement .
6.3 copy of new agreement.
7.company computer card.
8.company electricity bill.
9.company CR
10.Company Municipal registration.
11.6 months bank statement.

with all this document go to labor department. submit the application ,if the application is accepted go to attestation department and attest the agreement . you will get message in your mobile with application number ,you will get the message if the application is accepted or rejected with in 2-3 days . if accepted after7 days go to emigration for stamping the new visa in passport.

Note - don't apply for any higher post like manger .if you apply for it they will ask you to go and visit higher authorized person for the approval. rest all depends on your luck.