Changing the FLAGS field

To change the FLAGS field, prepare a keyed list where the keys are the individual flags and each key's value is that flag's boolean value. Legal boolean values are 0, 1, on, off, true, and false.

For example:

Input: msgmetaset message6 FLAGS { <some flags\ keyed list...> }
Input: msgmetaset message6 FLAGS { {expect_reply\ TRUE} {proto_nak 0} }