Rules governing the notice period upon termination of employment

Dear Sir,

I would like to know more about the notice period to terminate a person in Ajman Free Zone and how to implement it.

My friend got a notice period upon termination without a specific time mentioned in the letter. Instead, it mentioned, "as extended up to handover".

Is this valid as can it be extended for more than the agreed terms, which is 1 month from the termination or resignation as per the labour agreement?

Please advise. My friend is working at this company as a manager for the last 5 years, and the contract is unlimited. Salary is AED 30K.