Well, in this particular case, the spells wouldn't cause any problem at all--provided, that is, that you're going by the method Armen describes, hacking your character down to Level 1, changing class, and Leveling Up from there. If you were going from a Fighter/Druid to a Fighter/Cleric, you would want to remove all the Druid-only spells. But you're not changing to a
Fighter/Cleric, you're going to a
Ranger/Cleric, and Ranger/Clerics learn ALL of the Priest spells anyway. (Still, as long as you're doing this, go ahead and delete Harper's Call. She'll hardly need it as she'll have Raise Dead, but I'd like to see if the spell gets given back to her upon Level-Up.)
A resonably good, comprehensive (including a breakdown of the Priest spell tables), and spoiler-free guide to the game can be found
here.
[EDIT] WTF? The text contains the full link (ends in "bgguide.htm"), but the link itself is truncated to "bgguid". Whatever. Copy & paste this:
http://www.geocities.com/sixospades/bg/bgguide.htm