The output phases of two ADF4371 can be matched by shifting the output signals using Phase adjust feature. The phase difference between two parts should be measured by using an extra circuitry.
Phase resync feature is not supported in ADF4371 and ADF4372.
Table 33 for REG0023 on page 34 of the ADF4371 data sheet specifically mentions a phase resync capability, using bits [5:4].
Are you saying that this function is not supported by the ADF4371 or ADF4372 chips?