                               No. 89-184

               IN THE SUPREME COURT OF THE STATE OF MONTANA
                                   1989



IN RE THE MARRIAGE OF
ROBERT L. RYAN,
                 Petitioner and Appellant,
         and
SHIRLEY J. RYAN,
                 Respondent and Respondent.




APPEAL FROM:     District Court of the First Judicial ~istrict,
                 In and for the County of Lewis & Clark,
                 The Honorable Jeffrey Sherlock, Judge presiding.

COUNSEL OF RECORD:
         For Appellant:
                 J. Cort ~arrington,Jr., Helena, Montana
         For Respondent:
                 Shirley J. Ryan, pro se, paradise Valley, ~rizona



                                   Submitted on ~riefs: Aug. 10, 1989
                                     Decided:   September 7, 1989

Filed:
Chief Justice J. A. Turnage delivered the Opinion of the Court.
     The First Judicial District Court, Lewis and Clark County,
granted a decree of dissolution to appellant Robert L. Ryan and
respondent Shirley J. Ryan and ordered the appellant to pay
respondent $9,380 to fulfill his child support obligations. Robert
Ryan appeals the child support judgment alleging that it is an
improper modification of the parties1 separation agreement because
it creates a retroactive child support obligation. We affirm.
     Did the District Court err in ordering the husband to pay
child support to the wife when the separation agreement required
the husband to support children in his custody and those children
subsequently moved to the wife's home?
     The episodic marriage of Shirley and Robert Ryan began on
January 24, 1959 and produced four children: Cheryl, Robert, Jr.,
Patrick and Michael. The parties divorced in 1973 and remarried
two years later. On September 20, 1976, they entered a decree of
legal separation which incorporated their separation agreement.
Shirley petitioned the District Court for dissolution in 1986 but
declined to complete the matter until Robert filed for dissolution
on September 27, 1988.
     The separation agreement, which remained in effect until the
final decree of dissolution, provided for a balanced division of
the family property, obligations and children. Shirley assumed
custody of Cheryl and Robert, Jr., while Robert took custody of
Patrick and Michael.     The agreement also provided for child
support:
          Husband agrees to be responsible for and
          support Patrick Sean Ryan and Michael Erin
          Ryan and Wife agrees to be responsible for and
          support Cheryl Ann Ryan and Robert Lee Ryan,
          Jr.
Each party was to retain medical insurance and tax deductions for
the children in their custody.      Shirley testified during the
dissolution proceedings that she took a lesser amount of the family
property to compensate for the earlier date at which Cheryl and
Robert, Jr., would reach emancipation.
     This arrangement continued until February 1980 when Patrick
left his father and went to live with his mother. By that time,
Cheryl and Robert, Jr., had both attained the age of majority. In
December 1984, Michael also moved in with his mother, but returned
to his father's home in November 1986. In May 1988, Michael again
left his father to live with his mother.
     On July 31, 1986, Shirley filed an application for a decree
of dissolution, child support, and modification of custody. Among
other things, she requested that the court order Robert to pay
retroactive and continuing child support for the time that Patrick
and Michael lived in her home. Robert entered a motion to quash.
After denying Robert's motion, the District Court granted the
decree of dissolution as of February 24, 1989. The District Court
found that the parties had agreed to a mutual modification of their
1976 separation agreement by allowing Patrick and Michael to live
with their mother. The court found that Patrick and Michael, both
emancipated at that time, had lived with Shirley for forty months
and twenty-nine months respectively. Applying the Supreme Court's
Guidelines for Child Support, the District Court ordered Robert to
pay Shirley $9,380 at $200 per month. Robert now appeals that
decision.
     We agree with the District Court's equitable and well-reasoned
decision.
     The general rule on modification of child support provides
that, "a decree may be modified by a court      . . .    only as to
installments accruing subsequent to actual notice to the parties
of the motion for modification.                                  .
                                   Section 40-4-208 (I), MCA (1987)
This Court, however, has carved out an equitable exception to the
statute.
          These legal principles, however valid they may
          be as a general rule, are rendered impotent
          when the parties mutually agree that they be
          ignored and also carry out such agreement in
          actual fact  ....
State of Washington ex rel. Blakeslee v. Horton (1986), 222 Mont.

     In the separation contract, Robert agreed that he would have
custody and support responsibilities for Patrick and Michael. The
District Court found that Robert at least tacitly assented to
modification of the arrangement by allowing Patrick and Michael to
live with their mother.
     As the District Court noted, this case is notably similar to
In Re Marriage of Sabo (Mont. 1986), 730 P.2d 1112, 43 St.Rep.
2175. In Sabo the divorce decree and settlement agreement provided
that the couple's children would live with the wife and the husband
would pay child support. We held that the wife was not entitled
to child support after she gave residential custody of the children
to her former husband. Sabo, 730 P.2d at 1114, 43 St.Rep. at 2178-
79.
     As a corollary to Sabo, the parent who takes residential
custody of children pursuant to a mutual modification of custody
provisions is entitled to child support. Parents are responsible
for the support of their offspring. In Re Support of Krug (Mont.
1988), 751 P.2d 171, 174, 45 St.Rep. 446, 449; State v. Hubbard
(1986), 222 Mont. 156, 160, 720 P.2d 1177, 1179; In Re Marriage of
Hickey (1984), 213 Mont. 38, 45, 689 P.2d 1222, 1226.         Child
support is for the benefit of the children. Kruq, 751 P.2d at 173,
45 St.Rep. at 448. It should flow toward the children regardless
of the diversionary machinations of the parents.
     The present case is less one of retroactive modification than
it is a simple case of collecting reasonable support based on
custody.    Robert had a legal, moral, and contractual duty to
support Patrick and Michael, and he avoided that duty while they
were living with Shirley. Robert now complains that Shirley will
reap a windfall under the District Court Is order. To the contrary,
the order will prevent Robert from reaping a windfall at Shirley's
expense.
     Af finned.


                              &?PAlY7'z  Chief Justice



We concur:




     /
          Justices
