Hi

there are couple of threads about similar topic in this section of the forum , so please take a look (i know some are not about refunds but i want to show you who you are dealing with)
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Forced overnight layover by Aeromexico. No offer of hotel and refused to protect onto

AMS - MEX, (AM26) HELP, please..

Aeromexico - How do I get them to refund ticket for cancelled flight

Aeromexico refuses to refund, any guidance?

AeroMexico 1/15/2021 deadline to file proof of claim for refund

Aeromexico online ticket change

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About AM (or any other airline in general) , here are my 2 cents i keep repeating since beginning of pandemic = with current situation and lack of flexibility from the airline in case of problem, i would not recommend anyone to book tickets with AM further than 30 days before departure

if i remember correctly , you could ask for vouchers and then reuse it later . For rebooking , it should be possible , but they will probably ask you to pay the difference in case new price is higher