62-6. On days of thanksgiving, he should give information respecting the authority and providences which call for the observance; and he should spend more than the usual time in giving thanks, agreeably to the occasion, and in singing psalms or hymns of praise. On these days, the people should rejoice with holy gladness of heart; but their joy should be tempered with reverence, that they indulge in no excess or unbecoming levity.

DIGEST : Our current PCA text dates to PCA 1973 and has its origin with PCUS 1929, while still being very similar to that of PCUS 1894.

BACKGROUND AND COMPARISONO :
1. PCA 1973, Adopted text, DfW 16-7 [M1GA, Appendix, p. 161]
2. Continuing Presbyterian Church 1973, Proposed DfW text, 16-7, p. 76
3. PCUS 1933, XVI, §379
4. PCUS 1929, XVI, §379
On days of thanksgiving, he should give information respecting the authority and providences which call for the observance; and he should spend more than the usual time in giving thanks, agreeably to the occasion, and in singing psalms or hymns of praise. On these days, the people should rejoice with holy gladness of heart; but their joy should be tempered with reverence, that they indulge in no excess or unbecoming levity.

1. PCUS 1927, XV, §373–VIII
2. PCUS 1894, XV-8
On days of thanksgiving, he is to give the like information respecting the authority and providences which call for the observance of them; and to spend a more than usual part of the time in the giving of thanks, agreeably to the occasion, and in singing psalms or hymns of praise.
It is the duty of the people on these days to rejoice with holy gladness of heart; but let trembling be so joined with their mirth, that no excess or unbecoming levity be indulged.

COMMENTARY:
Morton H. Smith, Commentary on the Book of Church Order, 6th edition, 2007, p. 454.
Here we have practical guidelines for calling for a day of fasting or thanksgiving. Enough notice should be given so that the regular affairs may be covered, and the appropriate services may be attended.