#include <bits/stdc++.h>
using namespace std;

using ii = pair<int, int>;

int T, n, m, dr[] = {-1, -1, -1, 0, 0, 1, 1, 1}, dc[] = {-1, 0, 1, -1, 1, -1, 0, 1};
char f[105][105];
bool bad, vis[105][105];
queue<ii> Q;

char chk(int r, int c) {
	if (f[r][c] != '?') {
		return 0;
	}
	if (r > 1 && c > 1) {
		if (f[r - 1][c] != '?' && f[r][c - 1] != '?' && f[r - 1][c - 1] != '?' && f[r - 1][c] == f[r][c - 1] && f[r][c - 1] != f[r - 1][c - 1]) {
			return f[r - 1][c];
		}
	}
	if (r > 1 && c < m) {
		if (f[r - 1][c] != '?' && f[r][c + 1] != '?' && f[r - 1][c + 1] != '?' && f[r - 1][c] == f[r][c + 1] && f[r - 1][c] != f[r - 1][c + 1]) {
			return f[r - 1][c];
		}
	}
	if (r < n && c > 1) {
		if (f[r + 1][c] != '?' && f[r][c - 1] != '?' && f[r + 1][c - 1] != '?' && f[r][c - 1] == f[r + 1][c] && f[r + 1][c - 1] != f[r][c - 1]) {
			return f[r][c - 1];
		}
	}
	if (r < n && c < m) {
		if (f[r + 1][c] != '?' && f[r][c + 1] != '?' && f[r + 1][c + 1] != '?' && f[r + 1][c] == f[r][c + 1] && f[r + 1][c + 1] != f[r + 1][c]) {
			return f[r + 1][c];
		}
	}
	return 0;
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> T;
	while (T--) {
		bad = 0;
		cin >> n >> m;
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				cin >> f[i][j];
				vis[i][j] = 0;
			}
		}
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				if (chk(i, j)) {
					Q.emplace(i, j);
				}
			}
		}
		while (!Q.empty()) {
			auto [r, c] = Q.front();
			Q.pop();
			if (vis[r][c]) {
				continue;
			}
			vis[r][c] = 1;
			f[r][c] = chk(r, c);
			for (int k = 0; k < 8; k++) {
				int nr = r + dr[k], nc = c + dc[k];
				if (1 <= nr && nr <= n && 1 <= nc && nc <= m && chk(nr, nc)) {
					Q.emplace(nr, nc);
				}
			}
		}
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				if (f[i][j] == '?') {
					int cnt[2] = {};
					for (int k : {0, 1, 3}) {
						int ni = i + dr[k], nj = j + dc[k];
						if (1 <= ni && ni <= n && 1 <= nj && nj <= m) {
							cnt[f[ni][nj] == 'W']++;
						}
					}
					if (cnt[0] < cnt[1]) {
						f[i][j] = 'W';
					} else {
						f[i][j] = 'B';
					}
				}
			}
		}
		for (int i = 2; i <= n; i++) {
			for (int j = 2; j <= m; j++) {
				if (f[i - 1][j - 1] != f[i - 1][j] && f[i - 1][j] == f[i][j - 1] && f[i - 1][j - 1] == f[i][j]) {
					bad = 1;
				}
			}
		}
		if (bad) {
			cout << "NO\n";
		} else {
			cout << "YES\n";
			for (int i = 1; i <= n; i++) {
				for (int j = 1; j <= m; j++) {
					cout << f[i][j];
				}
				cout << '\n';
			}
		}
	}
}