Hi sir , i am working in IHG hotel in dubai , and...

We would like to inform you that the labor law does not prevent the employee from being assigned a job that is different from that of the contract but the law also does not allow for the reduction of the salary in the event of a change of profession. The Labor Law also stipulates that an additional wage should be paid if the worker works for additional hours, and If the employer does not pay the additional wage, a complaint can be filed with the Ministry of Labor.
Nevertheless, you can file a complaint with the Ministry of Human Resources and Emiratisation, if the job differs from the profession registered in the employment contract.
Here is the text of the UAE Labor Law relating to your inquiry:
Article 65
The maximum normal working hours for adult workers shall be eight hours in the day, 48 hours in the week. They may be increased to nine hours a day in commercial establishments, hotels, cafeterias, security services and such other businesses as may be added by resolution of the Minister of Labour and Social Affairs. The daily working hours may be reduced by resolution of the Minister of Labour and Social Affairs, in the case of arduous or health-hazardous work. Two during the month of Ramadan shall reduce the normal working hours. The periods spent by a worker in traveling between his home and place of work shall not be included in his working hours.
Article 67
Where the work circumstances require a worker to work more than the normal number of hours, any period worked in excess shall be treated as overtime, for which the worker shall receive the wage stipulated for his normal working hours, plus a supplement of at least 25% of that wage.
Article 68
Where the work circumstances require a worker to work overtime between 9 p.m. and 4 a.m. he shall be entitled in respect of such overtime to the wage stipulated for his normal working hours, plus a supplement of at least 50% of that wage.