Hello dowchee It is always best practice to have a backup of your data just in case there is any issue in doing the upgrade.  With that being said you should be able to change out the H310 with the H710 and do an import of the configuration and all should work just fine.  But again I would not do this unless you had no way to backup your data.   Please let us know if you have any other questions.
Hello,  We have NX400 with h310 and four 3TB hard disks. (raid 5) Can we replace new h710 card without data backup?  Thanks 
upgrade from h310 to h710