Please excuse me, I edited the post and it changed the formatting.  I get the following when attempting to put NO in front of the command:

console(config-if-Gi1/0/1)#no switchport general allowed vlan add 10,14 tagged

                                                                              ^

% Invalid input detected at '^' marker.

(hash mark is below the first L in allowed)

Well, that was the first thing I tried.  Unfortunately it does not work.

console(config-if-Gi1/0/1)#no switchport general allowed vlan add 10,14 tagged                                                                              ^

% Invalid input detected at '^' marker.

(the hash mark is below the first letter "L" in allowed)

So I attemtped some variations, I tried:

console(config-if-Gi1/0/1)#no switchport general

Command not found / Incomplete command. Use ? to list commands.

I tried that one as well, received another error:

console(config-if-Gi1/0/1)#no switchport mode general

                                                                          ^

% Invalid input detected at '^' marker

(hash mark is below G in general)

I thought perhaps I could change the mode from general to access, so I tried

#switchport mode access

This appears to go through with no errors, but Show Run displays no change.  I ran SHUT and NO SHUT to recycle the port, but still no change.  Typing in

#switchport allowed vlan 10

results in this:

switchport general allowed vlan add 10,14 tagged
switchport access vlan 10

Is there a command that will reset the port to its default configuration?

no switchport mode

resets to the default config for the port.

Page 829 ftp.dell.com/.../powerconnect-m6220_Reference%20Guide_en-us.pdf

Not work