Can registered users update their information with a password?

Can registered users update their information with a password?

Hi people,

I have a question which I couldn't find the answer in the support forums.

I have developed an online database for volunteers. www.evsturkey.com
The volunteers are filling the form and make their registeration.

Now I want to create another FORM for updating the records.
I found out to update a data in a from from another from with "STATELESS FORM".
But what I want to do is something further:

When the volunteers make their registaration I want them to define a password in the "Password Field".

Than in the update form, when volunteers choose their email address from the "Look Up Field"
I want them to write their passwords. And if the password is the same with the field of password in the original form then the update should happen.

How can I do this?

Thanks in advance for yoru help.

Mustafa ERDOGAN