It is absolutely fine to have another player take your turns if you will not be able to.
If you can find someone who will agree to sit your games, what you're going to want to do is:
1. Change the password on your account. (Control Panel -> Profile -> Edit Account Settings)
2. Give the new password to your sitter.
3. Enjoy your vacation while your sitter makes sure you don't miss any turns.
4. When you get back, change your password to what it originally was.
5. Thank your sitter for taking care of your turns.
sempai