Name on JR passes. Will this be a problem?

Hello,

I just bought three JR passes and received exchange coupons today. But I just saw that my husband first name are slightly different from his passport full name.

Its ‘Dan’ on the exchange coupon but ‘Daniel’ on the passport.

Shoul I change this and how do I make a change?
Or if its okay?
Thank you very much
Momo