How many? Do you have a bucket or a large enough tupperware container to house them to acclimate?
1. Take enough water from the old tank and put it in the bucket.
2. Transfer fish to bucket.
3. Add a cup +/- of water from new tank to bucket (depending on how much water you start with, you may have to decrease this amount). Don't replace more than say 15% at one time.
4. Remove a cup of water from the bucket and discard.
5. Repeat steps 3 and 4 maybe three or four times over about 30 minutes..
6. Add fish to new tank with a net (do not dump them directly in.)
7. Discard remaining water in bucket.
8. Top off both tanks with treated water if necessary.
If they're both tanks you set up and filled with water from the same source, then there really shouldn't be that much to acclimate them to. Even if there were, I almost never bother with anything more than getting the temperatures fairly close.