Thank You For Thank You Letter to someone for helping in your absence
Dear {Recipient},
Thank you so much for covering for me while I was {reason for your absence}. To be honest, I wasn't surprised to come back to {an organized desk/zero missed deadlines/etc.}. I know that my work was in capable hands.
I will be more than happy to return the favor should the opportunity arise. Thanks again!
Best,
{Your Name}