Some retraining options require you to work with a trainer. If no suitable trainer is available, the GM might allow you to retrain yourself by spending twice the normal time. Even if you train yourself, you must still pay the cost for training (though you don’t double the cost as you do the time). Any option that requires a trainer also requires some kind of training facility for that activity.
Class Level
In general, it takes 7 days to retrain one level in a class into one level in another class. Some classes are more suited for this kind of retraining, as they have a similar focus or purpose—this is called retraining synergy. If your old class has retraining synergy with your new class, retraining that class level takes only 5 days instead of 7 days. Determine class retraining synergies according to Table 3 –8: Retraining Synergies.
Summoner: Sorcerer, witch, wizard
First time playing summoner and we're in level 5 in the campaign, I chose the master summoner archetype and was naive enough to choose unchained summoner, which is an oxymoron as it turns out. So I spoke with my DM and he agreed to allow me to retrain. Due to the nature of the campaign, down time is very limited, so he was benevolent enough to allow training to happen instantaneously, but I still have to pay the gold price. My question is how much gold does it cost to retrain 5 levels of unchained summoner to "normal" summoner, and
1) why is unchained --> summoner not considered a synergy class?
2) So is it 10x5x7=350 x 5 levels 1750 gp total?
3) or 10x5x5=250 x 5 levels 1250 gp?
I only ask because we're a party of six, and even without spending practically any of my gold I only have 1500, which means I need to sell that +1 ring of protection I picked up in Chapter 1.
Master Summoner should be focusing purely on the summons and flooding the field, so I don't see being unchained bringing you down that much. But unchained summoner was partly a purposeful nerf to the spells and eidolon. There are also some wonky additions to the eidolon, that are fine for some builds, but break the amount of freedom had with the regular summoner. These nerfs were because the summoner was considered too strong, though the other eidolon changes just seemed to be for the sake of change.
The rules for retraining are older than the unchained classes. Personally, I think it'd be closer to retraining an archetype, but your DM may disagree.
Note that you can never be an unchained-summoner 4/summoner 1, so the class retraining shouldn't work for this.
These classes can be used alongside their original counterparts (although individual characters must use one version or the other exclusively).