(a) The citation shall be made at least 21 days prior to the time appointed for such examination or hearing, except when otherwise specially provided for in this act.

(b) Service of the citation may be accepted by any or all persons therein named, by endorsing their acceptance in writing thereon.

(c) The citation may be served by any sheriff or constable in this State upon any person therein named residing or being in this State, in the same manner as an ordinary writ of summons.