I am just a layman but assuming you have confirmed tickets you shall be offered the choice between:
1. Full refund
OR
2. Rerouting on the same day
OR
3. Date change free of charge + hotel accommodations if necessary
Airlines will usually present the traveller with only option 1 and 3 (leaving out accommodations). However, as per the EU-regulation the passenger can make the choice between any of these three, not the airline.
I would call them up with a couple of rerouting suggestions (search for good ones on matrix.itasoftware.com for example), if award seats are available or if it is a partner airline or not
does not matter. If they don't accept these speak to a supervisor. If still refused then tell them your option is nr 2 (Article 8(1)(b) and have them send you their suggestion for comparable travel on the same day. If still refused do the same in writing.
The airline might say that the EU-rights don't apply because it is more than two weeks before departure, however the 2-week rules only applies for
compensation not for rerouting/refund.
You can also ask for advise at
www.flightmole.com/forum
Good luck and let us know how it turns out!