Usually not. Since we schedule sessions out in advance, there will likely be someone scheduled after you. If that happens, there is simply no way to extend you session. Sorry.
If you are trying to decide between two different lengths of session (e.g. 1 1/2 hours vs 2 hours), always pick the longer session. We will definitely use it.
If you are still unsure of the right session length, please feel free to contact us online or call us at (313) 883-9500 to discuss it.