Full Slate attempts to match clients to an existing client record based on the name, email and phone number. As long as the information in those fields is not different, then the software should match a new appointment to the appropriate client record. Note that the name field needs to be a close, but not exact, match...so for example, Patty Jones and Patti Jones should match up.
However, because Full Slate lets clients book appointments without registering (this would otherwise be a barrier to client booking) and allows multiple clients on the same email address to support scheduling by multiple family members (more on that at http://blog.fullslate.com/2011/04/04/multiple-clients-one-email-address/), duplicate client records do sometimes occur.
To merge duplicate client records, go to the Clients > List tab, select the client records you want to merge (up to a total of five) and click Merge. Conflicting information will be highlighted so you can select what you want in the merged record. Click OK and you’re done.