I am currently the proud player of a level 12 witch, about to start playing Eyes of the Ten; and it occered to me that I might want to pick up improved familiar next level. However, as my spells are stored in my familiar, I would lose them when I did this, so I checked the rules in the APG for replaceing a Witch Familiar whaich said
"If a familiar is lost or dies, it can be replaced 1 day later through a special ritual that costs 500 gp per witch level. The ritual takes 8 hours to complete. A new familiar begins knowing all of the 0-level spells plus two spells of every level the witch is able to cast. These are in addition to any bonus spells known by the familiar based on the witch's level and her patron (see patron spells)."
Now there are 2 possible ways that this could be interprated;
1: I lose all of my current spells known and gain 2 spells of each level i can cast + patron spell, which seems uneccisarily punative, as im effectively loseing 2 spells per spell level +1+ starting Int mod 1st level.
or 2: I lose all of my current spells known, and gain 2 spells per spell level + patron spells + 2 spells per witch level +3 + Int mod 1st level spells, which seems unecesarily generous, for 1 feat(improved familiar) or 500GP per character level(to replace a dead or unbonded familiar)
I looked through the errat document, and the FAQ's for the CRB, the APG, and Organized play, to see if any of them could shed some light on the issue, but the only referances I found to changeing familiars were the entry in the CRB FAQ saying
"This isn't addressed in the rules anywhere, but yes, you should be able to dismiss a familiar if you want to select a new one. However, you must still wait 1 week and pay 200 gp for the 8-hour ritual. Dismissing a familiar is ending a link between your soul and it, so it should probably take about an hour.
The exception to the above is if you take the Improved Familiar feat, which allows you to immediately replace your familiar with the new familiar, at no cost or time required (it is assumed this occurs during whatever preparations you make while leveling up)...." and the Organized play FAQ that says the you replace a familiar between adventures by paying all of the normal costs.